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1. Suppression of Edge Localized Modes in ITER Baseline Scenario in EAST using Edge Localized Magnetic Perturbations

Author

Xie, P., Sun, Y., Jia, M., Loarte, A., Liu, Y. Q., Ye, C., Gu, S., Sheng, H., Liang, Y., Ma, Q., Yang, H., Paz-Soldan, C. A., Deng, G., Fu, S., Chen, G., He, K., Jia, T., Lu, D., Lv, B., Qian, J., Wang, H. H., Wang, S., Weisberg, D., Wu, X., Xu, W., Yan, X., Yu, Y., Zang, Q., Zeng, L., Zhang, T., Zhou, C., Zhou, Z., Wan, B., and Team, the EAST

Subjects
Physics - Plasma Physics
Abstract

We report the suppression of Type-I Edge Localized Modes (ELMs) in the EAST tokamak under ITER baseline conditions using $n = 4$ Resonant Magnetic Perturbations (RMPs), while maintaining energy confinement. Achieving RMP-ELM suppression requires a normalized plasma beta ($\beta_N$) exceeding 1.8 in a target plasma with $q_{95}\approx 3.1$ and tungsten divertors. Quasi-linear modeling shows high plasma beta enhances RMP-driven neoclassical toroidal viscosity torque, reducing field penetration thresholds. These findings demonstrate the feasibility and efficiency of high $n$ RMPs for ELM suppression in ITER., Comment: 6 pages, 4 figures

Published
2024

2. Access and sustainment of ELMy H-mode operation for ITER Pre-Fusion Power Operation plasmas using JINTRAC

Author

Tholerus, E., Garzotti, L., Parail, V., Baranov, Y., Bonnin, X., Corrigan, G., Eriksson, F., Farina, D., Figini, L., Harting, D. M., Kim, S. H., Koechl, F., Loarte, A., Asp, E. Militello, Nordman, H., Pinches, S. D., Polevoi, A. R., and Strand, P.

Subjects
Physics - Plasma Physics
Abstract

In the initial stages of ITER operation, ELM mitigation systems need to be commissioned. This requires controlled flat-top operation in type-I ELMy H-mode regimes. Hydrogen or helium plasma discharges are used exclusively in these stages to ensure negligible production of neutrons from fusion reactions. With the expected higher L-H power threshold of hydrogen and helium plasmas compared to corresponding D and D/T plasmas, it is uncertain whether available auxiliary power systems are sufficient to operate in stable type-I ELMy H-mode. This has been investigated using integrated core and edge/SOL/divertor modelling with JINTRAC. Assuming that the L-H power threshold is well captured by the Martin08 scaling law, the presented simulations have found that 30 MW of ECRH power is likely required for the investigated hydrogen plasma scenarios, rather than the originally planned 20 MW in the 2016 Staged Approach ITER Baseline. However, past experiments have shown that a small helium fraction (~10 %) can considerably reduce the hydrogen plasma L-H power threshold. Assuming that these results extrapolate to ITER operation regimes, the 7.5MA/2.65T hydrogen plasma scenario is likely to access stable type-I ELMy H-mode operation also at 20 MW of ECRH., Comment: 22 pages, 10 figures

Published
2024

3. Quantification of locked mode instability triggered by a change in confinement

Author

Peterka, M., Seidl, J., Markovic, T., Loarte, A., Logan, N. C., Park, J. -K., Cahyna, P., Havlicek, J., Imrisek, M., Kripner, L., Panek, R., Sos, M., Bilkova, P., Bogar, K., Bohm, P., Casolari, A., Gribov, Y., Grover, O., Hacek, P., Hron, M., Kovarik, K., Tomes, M., Tskhakaya, D., Varju, J., Vondracek, P., Weinzettl, V., and Team, the COMPASS

Subjects
Physics - Plasma Physics
Abstract

This work presents the first analysis of the disruptive locked mode (LM) triggered by the dynamics of a confinement change. It shows that, under certain conditions, the LM threshold during the transient is significantly lower than expected from steady states. We investigate the sensitivity to a controlled $n = 1$ error field (EF) activated prior to the L-H transition in the COMPASS tokamak, at $q_{95} \approx 3$, $\beta_N \approx 1$, and using EF coils on the high-field side of the vessel. A threshold for EF penetration subsequent to the L-H transition is identified, which shows no significant trend with density or applied torque, and is an apparent consequence of the reduced intrinsic rotation of the 2/1 mode during this transient phase. This finding challenges the assumption made in theoretical and empirical works that natural mode rotation can be predicted by global plasma parameters and urges against using any parametric EF penetration scaling derived from steady-state experiments to define the error field correction strategy in the entire discharge. Furthermore, even at EFs below the identified penetration threshold, disruptive locking of sawtooth-seeded 2/1 tearing modes is observed after about 30% of L-H transitions without external torque., Comment: 15 pages, 13 figures, submitted to Nuclear Fusion

Published
2024

4. Heuristic predictions of RMP configurations for ELM suppression in ITER burning plasmas and their impact on divertor performance

Author

Frerichs, H., van Blarcum, J., Feng, Y., Li, L., Liu, Y. Q., Loarte, A., Park, J. -K., Pitts, R. A., Schmitz, O., and Yang, S. M.

Subjects
Physics - Plasma Physics
Abstract

A subspace of resonant magnetic perturbation (RMP) configurations for edge localized mode (ELM) suppression is predicted for H-mode burning plasmas at 15 MA current and 5.3 T magnetic field in ITER. Perturbation of the core plasma can be reduced by a factor of 2 for equivalent edge stability proxies, while the perturbed plasma boundary geometry remains mostly resilient. The striation width of perturbed field lines connecting from the main plasma (normalized poloidal flux $< 1$) to the divertor targets is found to be significantly larger than the expected heat load width in the absence of RMPs. This facilitates heat load spreading with peak values at an acceptable level below 10 MW m${}^{-2}$ on the outer target already at moderate gas fueling and low Ne seeding for additional radiative dissipation of the 100 MW of power into the scrape-off layer (SOL). On the inner target, however, re-attachment is predicted away from the equilibrium strike point due to increased upstream heat flux, higher downstream temperature and less efficient impurity radiation., Comment: submitted in Nuclear Fusion

Published
2024
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8. A new algorithm DEtectS critical Congenital Heart Disease at different altitudes: ANDES-CHD study

Author

Bravo-Jaimes, Katia, Vasquez-Loarte, Tania, Rojas-Camayo, Jose, Medina, Monica, Mejia, Christian R., Zapata-Galarza, Henry, Berrocal, Marilia, Orozco, Jeanette, Lozano, Daniel, Santivañez, Maryuri, Sangay, Carlos, Rosales, William, Mamani, Leddy, Macedo, Nelly, Coronado, Joel, Huaman, Gian, Marquez, Rafael, Li, Zhuo, Masood, Kiran M., Alejos, Juan, Reardon, Leigh, and Lin, Jeannette

Published
2024
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9. Extension of ELM suppression window using n=4 RMPs in EAST

Author

Xie, P., Sun, Y., Ma, Q., Gu, S., Liu, Y. Q., Jia, M., Loarte, A., Wu, X., Chang, Y., Jia, T., Zhang, T., Zhou, Z., Zang, Q., Lyu, B., Fu, S., Sheng, H., Ye, C., Yang, H., Wang, H. H., and Contributors, EAST

Subjects
Physics - Plasma Physics
Abstract

The q95 window for Type-I Edge Localized Modes (ELMs) suppression using n=4 even parity Resonant Magnetic Perturbations (RMPs) has been significantly expanded to a range from 3.9 to 4.8, which is demonstrated to be reliable and repeatable in EAST over the last two years. This window is significantly wider than the previous one, which is around q95=3.7pm0.1, and is achieved using n=4 odd parity RMPs. Here, n represents the toroidal mode number of the applied RMPs and q95 is the safety factor at the 95% normalized poloidal magnetic flux. During ELM suppression, there is only a slight drop in the stored energy (<=10%). The comparison of pedestal density profiles suggests that ELM suppression is achieved when the pedestal gradient is kept lower than a threshold. This wide q95 window for ELM suppression is consistent with the prediction made by MARS-F modeling prior to the experiment, in which it is located at one of the resonant q95 windows for plasma response. The Chirikov parameter taking into account plasma response near the pedestal top, which measures the plasma edge stochasticity, significantly increases when q95 exceeds 4, mainly due to denser neighboring rational surfaces. Modeling of plasma response by the MARS-F code shows a strong coupling between resonant and non-resonant components across the pedestal region, which is characteristic of the kink-peeling like response observed during RMP-ELM suppression in previous studies on EAST. These promising results show the reliability of ELM suppression using the n=4 RMPs and expand the physical understanding on ELM suppression mechanism., Comment: 25 pages, 11 figures

Published
2023

10. Screening blood donors for malaria, can we increase the number of eligible donors? An observational retrospective study

Author

María Dolores Corbacho-Loarte, Oihane Martín, Sandra Chamorro-Tojeiro, Clara Crespillo-Andújar, Francesca F. Norman, José A. Pérez-Molina, Marta González Sanz, Marta Rosas Cancio-Suárez, Gabriel Ruiz-Calvo, Alberto Richart López, José Miguel Rubio, Rogelio López-Vélez, and Begoña Monge-Maillo

Subjects
Transfusion, Malaria, Plasmodium, Asymptomatic infection, Immigrants, Arctic medicine. Tropical medicine, RC955-962, Infectious and parasitic diseases, RC109-216
Abstract

Abstract Background In non-endemic countries, malaria can be transmitted through blood donations from imported cases. To ensure standards of quality and safety of human blood, the European Union and Spanish national law, requires a deferral period, or a screening by immunological or genomic test among those donors with potential risk of malaria. Scientific societies, European Committee on Blood Transfusion, and Spanish Society of Haematology and Haemotherapy, refer only to the result of the immunological test. Methods An observational retrospective study was performed in potential donors with a positive immunological test for malaria done in the Regional Transfusion Center in Madrid and referred to the National Reference Unit for Tropical Diseases in Madrid between 2015–2020. At consultation a Polymerase Chain Reaction (PCR) for malaria was performed. Results During the study period, 121 possible donors attended for consultation at NRU-Trop. Median age: 38.5 (IQR:33–48); median time to consultation was 32 months (IQR:12.5–110). Eighty-two (67.8%) donors were migrants and thirty-nine were travellers (32.2%). ELISA values were available for 109 subjects (90.1%), 56 individual left malaria endemic area > 3 years before. All donors tested negative for Plasmodium spp PCR test (n = 121, 100%). Conclusions None of the subjects with a positive immunologic test deferred as blood donors had a positive genomic test. The presence of Plasmodium spp in collected blood was not detected by molecular techniques. To avoid the loss of potential blood donors, especially those with low incidence red blood cell antigens, as more precise microbiology techniques become available, updating the existing legislation becomes necessary to increase the availability of donated blood.

Published
2024
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11. Initial design concepts for solid boron injection in ITER

Author

J.A. Snipes, L.R. Baylor, A. Bortolon, F. Effenberg, E.P. Gilson, A. Loarte, R. Lunsford, R. Maingi, S. Meitner, F. Nespoli, S. Maruyama, A. Nagy, Z. Sun, J. Ulreich, and T. Wauters

Subjects
ITER, Wall conditioning, Boron injection, Boronization, Nuclear engineering. Atomic power, TK9001-9401
Abstract

As part of ITER’s consideration to change its first wall material from beryllium to tungsten, the ITER Organization has proposed studying the feasibility of real-time solid boron injection (SBI) into the plasma to coat the walls and divertor to supplement glow discharge boronization (GDB) [1]. Boron deposits getter oxygen and reduce sputtering of tungsten from plasma facing components (PFCs). Particularly in areas with significant plasma wall interactions, boron coatings are expected to be short-lived under high performance plasma conditions. The proposed SBI system aims to maintain boron layers in these areas to avoid excessive radiation from tungsten in the plasma as a risk mitigation to ensure ITER will be able to reach and sustain Q = 10 conditions. The system will be used sparingly, as redeposition of boron can lead to significant tritium retention, which must be minimized in ITER to comply with nuclear safety concerns. SBI is proposed to limit and precisely control the amount of boron injected in real-time during plasma operation. Here, some of the design requirements and initial concepts for an SBI system in ITER are presented based on previous results carried out with SBI systems on a number of tokamaks and stellarators around the world [2–18].Previous results using SBI systems installed by PPPL have injected boron particles from 5 µm–2 mm diameter at calibrated rates of 2–200 mg/s in real-time during plasma operation on AUG [4], DIII-D [5], EAST [6], KSTAR [7], LHD [8], TFTR [9], WEST [10], and W7-X [11,12], leading to improved wall conditions with reduced plasma impurity concentrations and radiated power and improved plasma performance. The boron is ionized in the plasma edge and then deposited on plasma-wetted surfaces. On AUG [4], EAST [6] and WEST [10] reduced tungsten sputtering sources were observed following several discharges with SBI. Extrapolation of these SBI results are presented to estimate the amount of boron needed for wall conditioning in ITER. Real-time SBI control requirements and plasma operation scenarios for ITER are also described.

Published
2024
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12. Optimizing beam-ion confinement in ITER by adjusting the toroidal phase of the 3-D magnetic fields applied for ELM control

Author

Sanchis, L., Garcia-Munoz, M., Viezzer, E., Loarte, A., Li, L., Liu, Y. Q., Snicker, A., Chen, L., Zonca, F., Pinches, S. D., and Zarzoso, D.

Subjects
Physics - Plasma Physics
Abstract

The confinement of Neutral Beam Injection (NBI) particles in the presence of n=3 Resonant Magnetic Perturbations (RMPs) in 15 MA ITER DT plasmas has been studied using full orbit ASCOT simulations. Realistic NBI distribution functions, and 3D wall and equilibria, including the plasma response to the externally applied 3D fields calculated with MARS-F, have been employed. The observed total fast-ion losses depend on the poloidal spectra of the applied n=3 RMP as well as on the absolute toroidal phase of the applied perturbation with respect to the NBI birth distribution. The absolute toroidal phase of the RMP perturbation does not affect the ELM control capabilities, which makes it a key parameter in the confinement optimization. The physics mechanisms underlying the observed fast-ion losses induced by the applied 3D fields have been studied in terms of the variation of the particle canonical angular momentum ($\delta P_{\phi}$) induced by the applied 3D fields. The presented simulations indicate that the transport is located in an Edge Resonant Transport Layer (ERTL) as observed previously in ASDEX Upgrade studies. Similarly, our results indicate that an overlapping of several linear and nonlinear resonances at the edge of the plasma might be responsible for the observed fast-ion losses. The results presented here may help to optimize the RMP configuration with respect to the NBI confinement in future ITER discharges.

Published
2022
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13. Cambios en el sistema de tenencia de la tierra entre fines del periodo colonial y los inicios del republicano: los efectos de los decretos de Bolívar en Huacho

Author

Luis Alberto Rosado Loarte

Subjects
independencia peruana, historia local, reparto de tierras, privatización de tierras, History (General), D1-2009, Latin America. Spanish America, F1201-3799
Abstract

Este estudio de caso busca analizar el efecto que produjo en el pueblo de Huacho el paso del tradicional reparto de tierras a los indígenas, ligado al pago del tributo, al proceso de privatización de las tierras de las comunidades como consecuencia de los decretos de Bolívar en 1824 y 1825, reafirmados por la Ley dada por el Congreso Constituyente en 1828, y si este reparto fue utilizado por fidelistas e insurgentes como estrategia para conseguir la fidelidad de los indígenas durante el proceso de independencia. Se inicia con un repaso de cómo se llevaba a cabo el reparto de tierras a fines de la colonia, para luego analizar la normatividad dada sobre la materia entre 1824 y 1828, con el fin de contextualizarlos y evaluar su impacto. Las fuentes primarias utilizadas son documentos judiciales, notariales y de juzgado de paz que se conservan el Archivo Regional de Lima.

Published
2023

14. Complete 3D MHD simulations of the current quench phase of ITER mitigated disruptions

Author

Artola, F. J., Loarte, A., Hoelzl, M., Lehnen, M., Schwarz, N., and team, the JOREK

Subjects
Physics - Plasma Physics
Abstract

Complete 3D simulations of the current quench phase of ITER disruptions are key to predict asymmetric forces acting into the ITER wall. We present for the first time such simulations for ITER mitigated disruptions at realistic Lundquist numbers. For these strongly mitigated disruptions, we find that the edge safety factor remains above 2 and the maximal integral horizontal forces remain below 1 MN. The maximal integral vertical force is found to be 13 MN and arises in a time scale given by the resistive wall time as expected from theoretical considerations. In this respect, the vertical force arises after the plasma current has completely decayed, showing the importance of continuing the simulations also in the absence of plasma current. We conclude that the horizontal wall force rotation is not a concern for these strongly mitigated disruptions in ITER, since when the wall forces form, there are no remaining sources of rotation., Comment: to be submitted to Nuclear Fusion

Published
2021
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16. Global health for rare diseases through primary care

Author

Baynam, Gareth, Hartman, Adam L, Letinturier, Mary Catherine V, Bolz-Johnson, Matt, Carrion, Prescilla, Grady, Alice Chen, Dong, Xinran, Dooms, Marc, Dreyer, Lauren, Graessner, Holm, Granados, Alicia, Groza, Tudor, Houwink, Elisa, Jamuar, Saumya Shekhar, Vasquez-Loarte, Tania, Tumiene, Biruté, Wiafe, Samuel Agyei, Bjornson-Pennell, Heidi, and Groft, Stephen

Published
2024
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18. Influencia glaciar en la composición y diversidad de la comunidad del fitoplancton marino en la Bahía Almirantazgo, Isla Rey Jorge, Antártida

Author

Katy Medina Marcos, Edwin Loarte, Sofia Rodriguez-Venturo, Maribel Baylón Coritoma, and Pedro M Tapia

Subjects
Antártida, Fitoplancton, Biodiversidad, Composición comunitaria, Distancia al glaciar, Biology (General), QH301-705.5
Abstract

El cambio climático ha contribuido a un retroceso rápido de los glaciares en la Península Antártica Occidental, presentando implicaciones potenciales para los ecosistemas marinos, especialmente las comunidades de fitoplancton. En el presente trabajo, se examinó la influencia de la cercanía de los frentes glaciares en la composición de fitoplancton en Bahía Almirantazgo, Antártida, durante el verano austral de 2020. Se establecieron 12 estaciones distribuidas a diferentes distancias del frente glaciar para recolectar muestras de agua a 3 profundidades para el análisis cuantitativo de fitoplancton. Se determinó que la comunidad en todas las estaciones estaba dominada por microorganismos nanoflagelados (

Published
2024
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19. Análisis de los factores de mortalidad empresarial en Huánuco: Causas, impactos y medidas de prevención

Author

Christian P. Martel.Carranza, Janeth L. Tello-Cornejo, Miguel B. Narvaez del Aguila, Adison J. Huamán-Lino, Milene C. Loarte-Alcedo, Alejandro A. Ocaña-Caqui, Jhosep R. Santos-Blas, and Lenen Reyes-Acosta

Subjects
cambio organizacional, economía de la empresa, empresa, empresario gestión, organización, Science (General), Q1-390
Abstract

Objetivo: Este artículo tiene como principal objetivo determinar los factores que se vinculan con la mortalidad empresarial en la provincia de Huánuco. Metodología: Se adoptó un enfoque cuantitativo y descriptivo para analizar la mortalidad empresarial en la provincia. La muestra se seleccionó mediante un muestreo estratificado proporcional, dividiendo la población en estratos según la actividad económica y el tamaño de la empresa. Se aplicó un muestreo aleatorio simple en cada estrato, resultando en una muestra de 157 emprendedores. Resultados: Los empresarios en Huánuco perciben un impacto económico significativo, con más del 69% indicando un gran impacto. Se destaca la importancia crítica de gestionar eficazmente los factores económicos y externos para la supervivencia empresarial. Conclusión: La percepción de los empresarios en Huánuco subraya la relevancia crítica de gestionar de manera eficiente los factores económicos y externos para garantizar la supervivencia y el éxito empresarial.

Published
2024
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20. Simulations of COMPASS Vertical Displacement Events with a self-consistent model for halo currents including neutrals and sheath boundary conditions

Author

Artola, F. J., Loarte, A., Matveeva, E., Havlicek, J., Markovic, T., Adamek, J., Cavalier, J., Kripner, L., Huijsmans, G. T. A., Lehnen, M., Hoelzl, M., Panek, R., team, COMPASS, and team, JOREK

Subjects
Physics - Plasma Physics
Abstract

The understanding of the halo current properties during disruptions is key to design and operate large scale tokamaks in view of the large thermal and electromagnetic loads that they entail. For the first time, we present a fully self-consistent model for halo current simulations including neutral particles and sheath boundary conditions. The model is used to simulate Vertical Displacement Events (VDEs) occurring in the COMPASS tokamak. Recent COMPASS experiments have shown that the parallel halo current density at the plasma-wall interface is limited by the ion saturation current during VDE-induced disruptions. We show that usual MHD boundary conditions can lead to the violation of this physical limit and we implement this current density limitation through a boundary condition for the electrostatic potential. Sheath boundary conditions for the density, the heat flux, the parallel velocity and a realistic parameter choice (e.g. Spitzer $\eta$ and Spitzer-H\"arm $\chi_\parallel$ values) extend present VDE simulations beyond the state of the art. Experimental measurements of the current density, temperature and heat flux profiles at the COMPASS divertor are compared with the results obtained from axisymmetric simulations. Since the ion saturation current density ($J_{sat}$) is shown to be essential to determine the halo current profile, parametric scans are performed to study its dependence on different quantities such as the plasma resistivity and the particle and heat diffusion coefficients. In this respect, the plasma resistivity in the halo region broadens significantly the $J_{sat}$ profile, increasing the halo width at a similar total halo current., Comment: Submitted to Plasma Physics and Controlled Fusion via the special issue of the Joint Varenna-Lausanne international workshop (October 12-16, 2020)

Published
2021
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21. Is Antiviral Treatment with Remdesivir at the Acute Phase of SARS-CoV-2 Infection Effective for Decreasing the Risk of Long-Lasting Post-COVID Symptoms?

Author

César Fernández-de-las-Peñas, Anabel Franco-Moreno, María Ruiz-Ruigómez, Estibaliz Arrieta-Ortubay, Pablo Ryan-Murua, Carlos Lumbreras-Bermejo, Pablo del-Valle-Loarte, Oscar J. Pellicer-Valero, Rocco Giordano, Lars Arendt-Nielsen, Isabel Martín-Garrido, and Juan Torres-Macho

Subjects
antiviral, remdesivir, long-COVID, post-COVID-19, Microbiology, QR1-502
Abstract

The aim of this study was to investigate the effects of administrating Remdesivir at the acute COVID-19 phase on developing post-COVID symptoms in previously hospitalized COVID-19 survivors by controlling factors such as age, sex, body mass index, and vaccination status. A case-control study was performed. Hospitalized COVID-19 survivors who had received intravenous Remdesivir during the acute phase (n = 216) were matched by age, sex, body mass index, and vaccination status with survivors who did not receive antiviral treatment (n = 216). Participants were asked to self-report the presence of any post-COVID symptom (defined as a symptom that started no later than three months after infection) and whether the symptom persisted at the time of study (mean: 18.4, SD: 0.8 months). Anxiety levels (HADS-A), depressive symptoms (HADS-D), sleep quality (PSQI), and severity/disability (FIC) were also compared. The multivariate analysis revealed that administration of Remdesivir at the acute COVID-19 phase was a protective factor for long-term COVID development (OR0.401, 95%CI 0.256–0.628) and specifically for the following post-COVID symptoms: fatigue (OR0.399, 95%CI 0.270–0.590), pain (OR0.368, 95% CI 0.248–0.548), dyspnea at rest (OR0.580, 95%CI 0.361–0.933), concentration loss (OR0.368, 95%CI 0.151–0.901), memory loss (OR0.399, 95%CI 0.270–0.590), hair loss (OR0.103, 95%CI 0.052–0.207), and skin rashes (OR0.037, 95%CI 0.005–0.278). This study supports the potential protective role of intravenous administration of Remdesivir during the COVID-19 acute phase for long-lasting post-COVID symptoms in previously hospitalized COVID-19 survivors.

Published
2024
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22. Constructing a new predictive scaling formula for ITER's divertor heat-load width informed by a simulation-anchored machine learning

Author

Chang, C. S., Ku, S., Hager, R., Churchill, R. M., Hughes, J., Köchl, F., Loarte, A., Parail, V., and Pitts, R.

Subjects
Physics - Plasma Physics
Abstract

Understanding and predicting divertor heat-load width ${\lambda}_q$ is a critically important problem for an easier and more robust operation of ITER with high fusion gain. Previous predictive simulation data for ${\lambda}_q$ using the extreme-scale edge gyrokinetic code XGC1 in the electrostatic limit under attached divertor plasma conditions in three major US tokamaks [C.S. Chang et al., Nucl. Fusion 57, 116023 (2017)] reproduced the Eich and Goldston attached-divertor formula results [formula #14 in T. Eich et al., Nucl. Fusion 53, 093031 (2013); R.J. Goldston, Nucl. Fusion 52, 013009 (2012)], and furthermore predicted over six times wider ${\lambda}_q$ than the maximal Eich and Goldston formula predictions on a full-power (Q = 10) scenario ITER plasma. After adding data from further predictive simulations on a highest current JET and highest-current Alcator C-Mod, a machine learning program is used to identify a new scaling formula for ${\lambda}_q$ as a simple modification to the Eich formula #14, which reproduces the Eich scaling formula for the present tokamaks and which embraces the wide ${\lambda}_q^X{GC}$ for the full-current Q = 10 ITER plasma. The new formula is then successfully tested on three more ITER plasmas: two corresponding to long burning scenarios with Q = 5 and one at low plasma current to be explored in the initial phases of ITER operation. The new physics that gives rise to the wider ${\lambda}q_^{XGC} is identified to be the weakly-collisional, trapped-electron-mode turbulence across the magnetic separatrix, which is known to be an efficient transporter of the electron heat and mass. Electromagnetic turbulence and high-collisionality effects on the new formula are the next study topics for XGC1., Comment: 23 pages, 16 figures, submitted to Physics of Plasmas

Published
2020
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23. A future of extreme precipitation and droughts in the Peruvian Andes

Author

Emily R. Potter, Catriona L. Fyffe, Andrew Orr, Duncan J. Quincey, Andrew N. Ross, Sally Rangecroft, Katy Medina, Helen Burns, Alan Llacza, Gerardo Jacome, Robert Å. Hellström, Joshua Castro, Alejo Cochachin, Nilton Montoya, Edwin Loarte, and Francesca Pellicciotti

Subjects
Environmental sciences, GE1-350, Meteorology. Climatology, QC851-999
Abstract

Abstract Runoff from glacierised Andean river basins is essential for sustaining the livelihoods of millions of people. By running a high-resolution climate model over the two most glacierised regions of Peru we unravel past climatic trends in precipitation and temperature. Future changes are determined from an ensemble of statistically downscaled global climate models. Projections under the high emissions scenario suggest substantial increases in temperature of 3.6 °C and 4.1 °C in the two regions, accompanied by a 12% precipitation increase by the late 21st century. Crucially, significant increases in precipitation extremes (around 75% for total precipitation on very wet days) occur together with an intensification of meteorological droughts caused by increased evapotranspiration. Despite higher precipitation, glacier mass losses are enhanced under both the highest emission and stabilization emission scenarios. Our modelling provides a new projection of combined and contrasting risks, in a region already experiencing rapid environmental change.

Published
2023
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24. Understanding the reduction of the edge safety factor during hot VDEs and fast edge cooling events

Author

Artola, F. J., Lackner, K., Huijsmans, G. T. A., Hoelzl, M., Nardon, E., and Loarte, A.

Subjects
Physics - Plasma Physics, Physics - Computational Physics
Abstract

In the present work a simple analytical approach is presented in order to clarify the physics behind the edge current density behaviour of a hot plasma entering in contact with a resistive conductor. When a plasma enters in contact with a highly resistive wall, large current densities appear at the edge of the plasma. The model shows that this edge current originates from the plasma response, which attempts to conserve the poloidal magnetic flux ($\Psi$) when the outer current is being lost. The loss of outer current is caused by the high resistance of the outer current path compared to the plasma core resistance. The resistance of the outer path may be given by plasma contact with a very resistive structure or by a sudden decrease of the outer plasma temperature (e.g. due to a partial thermal quench or due to a cold front penetration caused by massive gas injection). For general plasma geometries and current density profiles the model shows that given a small change of minor radius ($\delta a$) the plasma current is conserved to first order ($\delta I_p = 0 + \mathcal{O}(\delta a^2)$). This conservation comes from the fact that total inductance remains constant ($\delta L = 0$) due to an exact compensation of the change of external inductance with the change of internal inductance ($\delta L_\text{ext}+\delta L_\text{int} = 0$). As the total current is conserved and the plasma volume is reduced, the edge safety factor drops according to $q_a \propto a^2/I_p$. Finally the consistency of the resulting analytical predictions is checked with the help of free-boundary MHD simulations., Comment: 10 pages, 7 figures

Published
2020
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28. Pathways to strengthen the climate resilience of health systems in the Peruvian Amazon by working with Indigenous leaders, communities and health officers

Author

Carol Zavaleta-Cortijo, Graciela Meza, Claudia L Vidal-Cuellar, Victoria Chicmana-Zapata, Ingrid Arotoma-Rojas, James D Ford, Hugo Rodríguez Ferruchi, Elida De-La-Cruz, Guillermo Lancha-Rucoba, Diego B Borjas-Cavero, Sonia Loarte, Ofelia Alencastre Mamani, Victoria I Peña Palma, Maria G Coronel-Altamirano, Ivonne Benites, Giovanna Pinasco, Rosa Valera, Marco Maguiña Huaman, Adolfo Urteaga-Villanueva, and César V Munayco

Subjects
Medicine (General), R5-920, Infectious and parasitic diseases, RC109-216
Published
2023
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29. Satellite constellations for trusted node QKD networks

Author

Vergoossen, Tom, Loarte, Sergio, Bedington, Robert, Kuiper, Hans, and Ling, Alexander

Subjects
Quantum Physics
Abstract

Quantum key distribution from satellites becomes particularly valuable when it can be used on a large network and on-demand to provide a symmetric encryption key to any two nodes. A constellation model is described which enables QKD-derived encryption keys to be established between any two ground stations with low latency. This is achieved through the use of low earth orbit, trusted-node QKD satellites which create a buffer of keys with the ground stations they pass over, and geostationary relay satellites to transfer secure combinations of the keys to the ground stations. Regional and global network models are considered and the use of inter-satellite QKD links for balancing keys is assessed., Comment: 12 pages

Published
2019
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31. Simulations of the stationary Q = 10 and the exit phase from the flat-top of an ITER 15MA baseline scenario: predictive JINTRAC simulation with a consistent treatment of D and T in the whole plasma

Author

F. Eriksson, E. Tholerus, G. Corrigan, Y. Baranov, X. Bonnin, D. Farina, L. Figini, L. Garzotti, S.H. Kim, F. Koechl, A. Loarte, E. Militello Asp, C. Olde, V. Parail, S.D. Pinches, A. Polevoi, and P. Strand

Subjects
ITER, integrated modelling, JINTRAC, scenario development, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Designing a robust termination scenario for a burning ITER plasma is a challenge that requires extensive core plasma and divertor modelling. The presented work consists of coupled core/edge/SOL/divertor simulations, performed with the JINTRAC code, to study the Q = 10 flat-top phase and exit phase of the ITER 15 MA/5.3 T DT scenario. The modelling utilizes the recently implemented option to treat deuterium and tritium separately in the SOL/divertor, enabling a consistent treatment of deuterium and tritium in the whole plasma volume, which is a unique capability of JINTRAC. In addition, these are the first JINTRAC simulations of this scenario that use a first-principles transport model to self-consistently model the ECRH power deposition and to include tungsten while keeping track of tungsten sputtering and accumulation. The flat-top simulations demonstrate the possibility of sustaining a steady state fusion Q of 10 using pure deuterium gas puffs together with DT mixed pellets, which is an option to make a more effective use of tritium. Simulations of the exit phase are set up sequentially, with each phase providing initial conditions for the next, starting with a density decay at full current and auxiliary power, and demonstrate the possibility of reducing the density robustly within a few seconds. Following the density decay, a subsequent auxiliary power ramp-down in H-mode is performed with a late H–L transition at low auxiliary power, which may provide an option for the optimization of the plasma termination. The final ramp-down phase consists of a current ramp-down in L-mode to 3.75 MA.

Published
2024
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32. WEST full tungsten operation with an ITER grade divertor

Author

J. Bucalossi, A. Ekedahl, and the WEST Team, J. Achard, K. Afonin, O. Agullo, T. Alarcon, L. Allegretti, F. Almuhisen, H. Ancher, G. Antar, Y. Anquetin, S. Antusch, V. Anzallo, C. Arnas, J.F. Artaud, M.H. Aumeunier, S.G. Baek, X.Y. Bai, M. Balden, C. Balorin, T. Barbui, A. Barbuti, J. Barlerin, J. Barra, V. Basiuk, T. Batal, O. Baulaigue, A. Bec, M. Becoulet, E. Benoit, E. Bernard, J.M. Bernard, M. Bernert, N. Bertelli, E. Bertrand, P. Beyer, J. Bielecki, P. Bienvenu, R. Bisson, B. Bliewert, G. Bodner, S. Bose, C. Bottereau, C. Bouchand, Y. Boumendjel, F. Bouquey, C. Bourdelle, J. Bourg, S. Brezinsek, F. Brochard, C. Brun, V. Bruno, H. Bufferand, A. Bureau, S. Burles, Y. Camenen, B. Cantone, E. Caprin, M. Carole, S. Carpentier-Chouchana, G. Caulier, F. Causa, N. Cazanave, N. Chanet, O. Chellai, Y. Chen, M. Chernyshova, P. Chmielewski, W. Choe, A. Chomiczewska, G. Ciraolo, F. Clairet, J. Coenen, L. Colas, G. Colledani, J. Colnel, P. Coquillat, E. Corbel, Y. Corre, X. Courtois, T. Czarski, A. Da Ros, R. Daniel, J. Daumas, M. De Combarieu, P. De Vries, C. Dechelle, F. Deguara, R. Dejarnac, J.M. Delaplanche, L.F. Delgado-Aparicio, E. Delmas, L. Delpech, C. Desgranges, P. Devynck, J. Denis, S. Di Genova, R. Diab, A. Diallo, M. Diez, G. Dif-Pradalier, M. Dimitrova, R. Ding, T. Dittmar, L. Doceul, M. Domenes, D. Donovan, D. Douai, L. Dubus, N. Dumas, R. Dumont, F. Durand, A. Durif, F. Durodié, D. Elbeze, S. Ertmer, A. Escarguel, F. Escourbiac, B. Esposito, K. Ezato, F. Faisse, J.L. Farjon, N. Faure, N. Fedorczak, P. Fejoz, F. Felici, C. Fenzi-Bonizec, F. Ferlay, L. Ferrand, L. Fevre, M. Firdaouss, L. Fleury, D. Flouquet, T. Fonghetti, A. Gallo, X. Garbet, J. Garcia, J.L. Gardarein, L. Gargiulo, P. Garibaldi, S. Garitta, J. Gaspar, E. Gauthier, S. Gazzotti, F. Gely, J. Gerardin, G. Gervasini, E. Geulin, M. Geynet, P. Ghendrih, I. Giacalone, C. Gil, S. Ginoux, S. Girard, E. Giroux, G. Giruzzi, M. Goniche, V. Gorse, T. Gray, E. Grelier, C. Grisolia, A. Grosjean, A. Grosman, O. Grover, D. Guibert, D. Guilhem, C. Guillemaut, B. Guillermin, R. Guirlet, J.P. Gunn, Y. Gunsu, T. Gyergyek, S. Hacquin, A. Hakola, J. Harris, J.C. Hatchressian, W. Helou, P. Hennequin, C. Hernandez, L. Hijazi, J. Hillairet, T. Hirai, G.T. Hoang, C. Honoré, M. Houry, A. Huart, G. Huijsmans, P. Huynh, M. Iafrati, F. Imbeaux, N. Imbert, I. Ivanova-Stanik, P. Ivanova, R. Jalageas, A. Jamann, C. Jammes, A. Jardin, L. Jaubert, G. Jiolat, E. Joffrin, C. Johnson, A. Jonas, A. Kirschner, C.C. Klepper, M. Komm, M. Koubiti, S. Kosslow, J. Kovacic, M. Kozeiha, K. Krieger, K. Krol, I. Kudashev, B. Lacroix, L. Laguardia, V. Lamaison, V. Lapleigne, H. Laqua, C. Lau, Y. Lausenaz, R. Lé, M. Le Bohec, N. Lefevre, N. Lemoine, E. Lerche, Y. Lesourd, L. Letellier, M. Lewerentz, Y. Li, A. Liang, P. Linczuk, C. Linsmeier, M. Lipa, X. Litaudon, X. Liu, J. Llorens, T. Loarer, A. Loarte, T. Loewenhoff, G. Lombard, J. Lore, P. Lorenzetto, B. Lu, A. Lumsdaine, R. Lunsford, T. Lunt, G. Luo, P. Magaud, P. Maget, J.F. Mahieu, P. Maini, P. Malard, K. Malinowski, P. Manas, L. Manenc, V. Maquet, Y. Marandet, C. Martin, E.J. Martin, P. Martino, M. Mayer, D. Mazon, S. Mazzi, P. Messina, L. Meunier, D. Midou, G. Miglionico, Y. Mineo, M. Missirlian, R. Mitteau, B. Mitu, D. Moiraf, P. Mollard, G. Momparler, V. Moncada, T. Mondiere, C. Monti, J. Morales, M. Moreau, Ph. Moreau, Y. Moudden, G. Moureau, D. Mouyon, M. Muraglia, T. Nakano, E. Nardon, A. Neff, F. Nespoli, J. Nichols, L. Nicolas, S. Nicollet, R. Nouailletas, M. Ono, V. Ostuni, O. Paillat, C. Parish, H. Park, H. Parrat, J.Y. Pascal, B. Pegourie, F.P. Pellissier, Y. Peneliau, M. Peret, E. Pignoly, G. Pintsuk, R. Pitts, C. Pocheau, A. Podolnik, C. Portafaix, M. Poulos, P. Prochet, A. Puig Sitjes, R. Ragona, M. Rasinski, S. Ratynskaia, G. Raup, X. Regal-Mezin, C. Reux, J. Rice, M. Richou, F. Rigollet, N. Rivals, H. Roche, S. Rodrigues, J. Romazanov, G. Ronchi, C. Ruset, R. Sabot, A. Saille, R. Sakamoto, B. Salamon, F. Samaille, A. Santagiustina, B. Santraine, Y. Sarazin, O. Sauter, Y. Savoie-Peysson, L. Schiesko, M. Scholz, J.L. Schwob, E. Serre, H. Shin, S. Shiraiwa, Ja. Signoret, O. Skalli-Fettachi, P. Sogorb, Y. Song, A. Spring, P. Spuig, S. Sridhar, B. Stratton, C. Talatizi, P. Tamain, R. Tatali, Q. Tichit, A. Torre, L. Toulouse, W. Treutterer, E. Tsitrone, E.A. Unterberg, G. Urbanczyk, G. Van Rooij, N. Varadarajan, S. Vartanian, E. Velly, J.M. Verger, L. Vermare, D. Vezinet, N. Vignal, B. Vincent, S. Vives, D. Volpe, G. Wallace, E. Wang, L. Wang, Y. Wang, Y.S. Wang, T. Wauters, D. Weldon, B. Wirth, M. Wirtz, A. Wojenski, M. Xu, Q.X. Yang, H. Yang, B. Zago, R. Zagorski, B. Zhang, X.J. Zhang, X.L. Zou, and the EUROfusion Tokamak Exploitation Team

Subjects
nuclear fusion, magnetic confinement, tokamak, divertor, WEST, ITER, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

The mission of WEST (tungsten-W Environment in Steady-state Tokamak) is to explore long pulse operation in a full tungsten (W) environment for preparing next-step fusion devices (ITER and DEMO) with a focus on testing the ITER actively cooled W divertor in tokamak conditions. Following the successful completion of phase 1 (2016-2021), phase 2 started in December 2022 with the lower divertor made entirely of actively cooled ITER-grade tungsten mono-blocks. A boronization prior the first plasma attempt allowed for a smooth startup with the new divertor. Despite the reduced operating window due to tungsten, rapid progress has been made in long pulse operation, resulting in discharges with a pulse length of 100 s and an injected energy of around 300 MJ per discharge. Plasma startup studies were carried out with equatorial boron nitride limiters to compare them with tungsten limiters, while Ion Cyclotron Resonance Heating assisted startup was attempted. High fluence operation in attached regime, which was the main thrust of the first campaigns, already showed the progressive build up of deposits and appearance of dust, impacting the plasma operation as the plasma fluence increased. In total, the cumulated injected energy during the first campaigns reached 43 GJ and the cumulated plasma time exceeded 5 h. Demonstration of controlled X-Point Radiator regime is also reported, opening a promising route for investigating plasma exhaust and plasma-wall interaction issues in more detached regime. This paper summarises the lessons learned from the manufacturing and the first operation of the ITER-grade divertor, describing the progress achieved in optimising operation in a full W environment with a focus on long pulse operation and plasma wall interaction.

Published
2024
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33. DIII-D research to provide solutions for ITER and fusion energy

Author

C.T. Holcomb, for the DIII-D Team:, J. Abbate, A. Abe, A. Abrams, P. Adebayo-Ige, S. Agabian, S. Ahmed, N. Aiba, N. Akcay, T. Akiyama, R. Albosta, P. Aleynikov, S. Allen, H. Anand, J. Anderson, Y. Andrew, M. Ashburn, A. Ashourvan, M. Austin, G. Avdeeva, D. Ayala, M. Ayub, E. Bagdy, S. Banerjee, K. Barada, L. Bardoczi, O. Bardsley, J. Barr, E. Bass, A. Battey, Z. Bayler, L. Baylor, T. Bechtel, M. Beidler, E. Belli, T. Benedett, Z. Bergstrom, M. Berkel, T. Bernard, N. Bertelli, R. Bielajew, G. Bodner, J. Boedo, R. Boivin, T. Bolzonella, P. Bonoli, A. Bortolon, S. Bose, M. Boyer, W. Boyes, L. Bradley, R. Brambila, A. Braun, D. Brennan, S. Bringuier, L. Brodsky, M. Brookman, J. Brooks, D. Brower, W. Brown, J. Buck, S. Buczek, D. Burgess, M. Burke, K. Burrell, J. Butt, R. Buttery, I. Bykov, P. Byrne, A. Cacheris, K. Callahan, J. Callen, D. Campbell, J. Candy, J. Canik, L. Cappelli, T. Carlstrom, R. Carr, W. Carrig, B. Carter, T. Carter, I. Carvalho, W. Cary, L. Casali, L. Ceelen, M. Cengher, M. Cha, R. Chaban, V. Chan, B. Chapman, I. Char, J. Chen, R. Chen, X. Chen, Y. Chen, J. Chiriboga, E. Cho, G. Choi, W. Choi, H. Choudhury, S. Chowdhury, C. Chrystal, Y. Chung, R. Churchill, R. Clark, M. Clement, J. Coburn, S. Coda, R. Coffee, C. Collins, J. Colmenares-Fernandez, W. Conlin, R. Coon, T. Cote, A. Creely, N. Crocker, C. Crowe, B. Crowley, T. Crowley, M. Curie, D. Curreli, A. Dal Molin, J. Damba, E. Dart, A. Dautt-Silva, K. Davda, A. De, N. de Boucaud, Y. de Jong, P. DE VRIES, A. de-Villeroche, G. DeGrandchamp, J. deGrassie, D. Demers, S. Denk, E. DeShazer, S. Di Genova, A. Diallo, A. Dimits, R. Ding, S. Ding, D. Donovan, X. Du, J. Dunsmore, A. Dupuy, J. Duran, A. Dvorak, F. Effenberg, N. Eidietis, D. Elder, D. Eldon, Y. Elsey, D. Ennis, K. Erickson, D. Ernst, M. Fajardo, H. Farre-Kaga, M. Fenstermacher, N. Ferraro, J. Ferron, A. Feyrer, P. Fimognari, R. Finden, D. Finkenthal, R. Fitzpatrick, S. Flanagan, B. Ford, W. Fox, S. Freiberger, L. Fu, K. Gage, V. Gajaraj, I. Garcia, F. Garcia, A. Garcia, M. Garcia Munoz, D. Garnier, A. Garofalo, A. Gattuso, B. Geiger, K. Gentle, Y. Ghai, K. Gill, F. Glass, P. Gohil, X. Gong, J. Gonzalez-Martin, Y. Gorelov, V. Graber, R. Granetz, C. Gray, C. Greenfield, B. Grierson, R. Groebner, W. Grosnickle, M. Groth, S. Gu, H. Guo, J. Guterl, W. Guttenfelder, R. Hager, S. Hahn, M. Halfmoon, J. Hall, V. Hall-Chen, F. Halpern, G. Hammett, X. Han, C. Hansen, E. Hansen, J. Hanson, M. Hanson, A. Harris, R. Harvey, S. Haskey, D. Hatch, W. Hayashi, A. Hayes, W. Heidbrink, J. Herfindal, J. Hicok, E. Hinson, T. Hisakado, C. Holcomb, C. Holland, L. Holland, E. Hollmann, A. Holm, I. Holmes, K. Holtrop, R. Hong, R. Hood, L. Horvath, S. Houshmandyar, N. Howard, E. Howell, W. Hu, Y. Hu, Q. Hu, Y. Huang, J. Huang, A. Huang, A. Hubbard, J. Hughes, D. Humphreys, J. Hurtado, A. Hyatt, K. Imada, V. Izzo, A. Jalalvand, S. Jardin, A. Jarvinen, Y. Jeon, H. Ji, X. Jian, L. Jian, Y. Jiang, C. Johnson, J. Johnson, M. Jones, S. Joung, P. Jouzdani, E. Jung, E. Kallenberg, R. Kalling, D. Kaplan, A. Kaptanoglu, D. Kellman, J. Kennedy, F. Khabanov, J. Kim, H. Kim, E. Kim, S. Kim, K. Kim, C. Kim, T. Kim, J. King, A. Kinsey, D. Kirk, D. Klasing, A. Kleiner, M. Knolker, M. Kochan, B. Koel, J. Koenders, M. Koepke, R. Kolasinski, E. Kolemen, E. Kostadinova, M. Kostuk, G. Kramer, R. Kube, N. Kumar, R. La Haye, F. Laggner, C. Lahban, H. Lan, R. Landry, R. Lantsov, L. Lao, C. Lasnier, C. Lau, R. Leccacorvi, J. Leddy, M. Lee, S. Lee, K. Lee, R. Lee, M. Lehnen, A. Leonard, E. Leppink, M. LeSher, J. Lestz, J. Leuer, N. Leuthold, G. Li, X. Li, Y. Li, L. Li, N. Li, Z. Li, D. Lin, Z. Lin, Y. Lin, E. Linsenmayer, J. Liu, D. Liu, C. Liu, Z. Liu, Y. Liu, A. Loarte-Prieto, S. Loch, L. LoDestro, N. Logan, J. Lohr, J. Lore, U. Losada Rodriguez, J. Loughran, M. Lowell, T. Luce, N. Luhmann, P. Lunia, R. Lunsford, L. Lupin-Jimenez, A. Lvovskiy, B. Lyons, X. Ma, J. MacDonald, T. Macwan, R. Maingi, M. Major, L. Malhotra, M. Margo, C. Marini, A. Marinoni, A. Maris, E. Martin, J. Mateja, R. Mattes, R. Maurizio, D. Mauzey, L. McAllister, G. McArdle, J. McClenaghan, K. McCollam, G. McKee, K. McLaughlin, A. McLean, V. Mehta, E. Meier, S. Meitner, J. Menard, O. Meneghini, G. Merlo, S. Messer, W. Meyer, C. Michael, D. Miller, M. Miller, J. Mitchell, E. Mitra, C. Moeller, M. Mohamed, S. Molesworth, K. Montes, S. Mordijck, S. Morosohk, A. Moser, D. Mueller, S. Munaretto, C. Murphy, C. Muscatello, R. Myers, A. Nagy, D. Nath, M. Navarro, R. Nazikian, T. Neiser, A. Nelson, P. Nesbet, F. Nespoli, P. Nguyen, D. Nguyen, R. Nguyen, J. Nichols, M. Nocente, L. Nuckols, R. Nygren, T. Odstrcil, M. Okabayashi, E. Olofsson, D. Orlov, D. Orozco, N. Osborne, T. Osborne, F. OShea, D. Pace, D. Packard, A. Pajares Martinez, C. Pakosta, C. Pan, M. Pandya, D. Panici, A. Pankin, Y. Park, J. Park, C. Parker, S. Parker, P. Parks, M. Parsons, S. Paruchuri, C. Paz-Soldan, T. Pederson, W. Peebles, B. Penaflor, E. Perez, L. Periasamy, R. Perillo, C. Petty, M. Pharr, D. Pierce, C. Pierren, S. Pierson, A. Pigarov, L. Pigatto, D. Piglowski, S. Pinches, R. Pinsker, R. Pitts, J. Pizzo, M. Podesta, Z. Popovic, M. Porkolab, Q. Pratt, G. Prechel, I. Pusztai, P. Puthan-Naduvakkate, J. Qian, X. Qin, O. Ra, T. Raines, K. Rakers, K. Rath, J. Rauch, C. Rea, R. Reed, A. Reiman, M. Reinke, R. Reksoatmodjo, Q. Ren, J. Ren, Y. Ren, M. Rensink, T. Rhodes, N. Richner, J. Ridzon, G. Riggs, J. Riquezes, P. Rodriguez Fernandez, T. Rognlien, G. Ronchi, L. Rondini, R. Rosati, A. Rosenthal, M. Ross, J. Rost, A. Rothstein, J. Roveto, J. Ruane, D. Rudakov, R. Rupani, G. Rutherford, S. Sabbagh, J. Sachdev, N. Sadeghi, A. Salmi, F. Salvador, B. Sammuli, C. Samuell, A. Sandorfi, C. Sang, D. Santa, J. Sarff, O. Sauter, H. Savelli, C. Schaefer, H. Schamis, J. Schellpfeffer, D. Schissel, L. Schmitz, O. Schmitz, P. Schroeder, K. Schultz, E. Schuster, F. Sciortino, F. Scotti, J. Scoville, A. Seltzman, J. Seo, J. Serrano, I. Sfiligoi, M. Shafer, R. Shapov, H. Shen, N. Shi, D. Shiraki, B. Short, R. Shousha, H. Si, C. Sierra, G. Sinclair, P. Sinha, G. Sips, C. Skinner, T. Slendebroek, J. Slief, R. Smirnov, S. Smith, D. Smith, G. Snoep, P. Snyder, W. Solomon, X. Song, A. Sontag, V. Soukhanovskii, D. Spong, J. Squire, G. Staebler, L. Stagner, T. Stange, P. Stangeby, E. Starling, S. Stewart, T. Stoltzfus-Dueck, S. Storment, E. Strait, D. Su, L. Sugiyama, P. Sun, Y. Sun, X. Sun, C. Sung, W. Suttrop, Y. Suzuki, R. Sweeney, B. Taczak, Y. Takemura, S. Tang, W. Tang, G. Tardini, D. Taussig, K. Teixeira, K. Thackston, D. Thomas, K. Thome, Y. Tinguely, M. Tobin, J. Tooker, A. Torrezan de Sousa, P. Traverso, G. Trevisan, E. Trier, D. Truong, C. Tsui, F. Turco, A. Turnbull, L. Turner, E. Unterberg, B. Van Compernolle, R. van Kampen, M. Van Zeeland, B. Victor, R. Vieira, E. Viezzer, S. Vincena, D. Vollmer, J. Wai, M. Walker, R. Waltz, W. Wampler, L. Wang, Y. Wang, H. Wang, Z. Wang, G. Wang, A. Wang, J. Watkins, M. Watkins, T. Watts, L. Webber, K. Weber, W. Wehner, X. Wei, D. Weisberg, A. Welander, A. Welsh, A. White, R. Wilcox, G. Wilkie, T. Wilks, M. Willensdorfer, H. Wilson, A. Wingen, M. Wu, D. Wu, S. Wukitch, J. Xia, R. Xie, Z. Xing, G. Xu, X. Xu, Z. Yan, X. Yang, L. Yang, S. Yang, J. Yang, M. Yoo, G. YU, J. Yu, A. Zalzali, A. Zamengo, V. Zamkovska, S. Zamperini, K. Zarrabi, E. Zeger, K. Zeller, L. Zeng, X. Zhang, J. Zhang, B. Zhang, B. Zhao, C. Zhao, Y. Zheng, Y. Zhu, J. Zhu, J. Ziegel, J. Zimmerman, and C. Zuniga

Subjects
DIII-D, tokamak, overview, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

The DIII-D tokamak has elucidated crucial physics and developed projectable solutions for ITER and fusion power plants in the key areas of core performance, boundary heat and particle transport, and integrated scenario operation, with closing the core-edge integration knowledge gap being the overarching mission. New experimental validation of high-fidelity, multi-channel, non-linear gyrokinetic turbulent transport models for ITER provides strong confidence it will achieve Q ⩾ 10 operation. Experiments identify options for easing H-mode access in hydrogen, and give new insight into the isotopic dependence of transport and confinement. Analysis of 2,1 islands in unoptimized low-torque IBS demonstration discharges suggests their onset time occurs randomly in the constant β phase, most often triggered by non-linear 3-wave coupling, thus identifying an NTM seeding mechanism to avoid. Pure deuterium SPI for disruption mitigation is shown to provide favorable slow cooling, but poor core assimilation, suggesting paths for improved SPI on ITER. At the boundary, measured neutral density and ionization source fluxes are strongly poloidally asymmetric, implying a 2D treatment is needed to model pedestal fuelling. Detailed measurements of pedestal and SOL quantities and impurity charge state radiation in detached divertors has validated edge fluid modelling and new self-consistent ‘pedestal-to-divertor’ integrated modeling that can be used to optimize reactors. New feedback adaptive ELM control minimizes confinement reduction, and RMP ELM suppression with sustained high core performance was obtained for the first time with the outer strike point in a W-coated, compact and unpumped small-angle slot divertor. Advances have been made in integrated operational scenarios for ITER and power plants. Wide pedestal intrinsically ELM-free QH-modes are produced with more reactor-relevant conditions, Low torque IBS with W-equivalent radiators can exhibit predator-prey oscillations in T _e and radiation which need control. High- β _P scenarios with q _min > 2, q _95 –7.9, β _N > 4, β _T –3.3% and H _98y2 > 1.5 are sustained with high density ( $\bar n$ = 7E19 m ^−3 , f _G –1) for 6 τ _E , improving confidence in steady-state tokamak reactors. Diverted NT plasmas achieve high core performance with a non-ELMing edge, offering a possible highly attractive core-edge integration solution for reactors.

Published
2024
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34. Overview of the KSTAR experiments toward fusion reactor

Author

Won-Ha Ko, S.W. Yoon, W.C. Kim, J.G. Kwak, K.L. Park, Y.U. Nam, S.J. Wang, J. Chung, B.H. Park, G.Y. Park, H.H. Lee, H.S. Han, M.J. Choi, Y.S. Na, Y. In, C.Y. Lee, M. Kim, G.S. Yun, Y.-C. Ghim, W.H. Choe, J.M. Kwon, J.P. Lee, W.C. Lee, Y.M. Jeon, K. Kim, J.H. Lee, G.W. Shin, J. Kim, J. Lee, S.H. Hahn, J.W. Lee, H.S. Kim, J.G. Bak, S.G. Lee, Y.H. Lee, J.H. Jeong, M.H. Woo, J.H. Kim, J.W. Juhn, J.S. Ko, C. Sung, H.W. Shin, J.M. Park, S.K. Kim, J.K. Park, N.C. Logan, S.M. Yang, E. Kolemen, Q.M. Hu, R. Shousha, J. Barr, C. Paz-Soldan, Y.S. Park, S.A. Sabbagh, K. Ida, S. Kim, A. Loarte, E. Gilson, D. Eldon, T. Nakano, T. Tala, and KSTAR Team

Subjects
FIRE-mode, machine learning (ML) control algorithm, long ELM-suppression, tungsten divertor, virtual KSTAR, high beta long pulse, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

The Korean Superconducting Tokamak Advanced Research has been focused on exploring the key physics and engineering issues for future fusion reactors by demonstrating the long pulse operation of high beta steady-state discharge. Advanced scenarios are being developed with the goal for steady-state operation, and significant progress has been made in high ℓ _i , hybrid and high beta scenarios with β _N of 3. In the new operation scenario called fast ion regulated enhanced (FIRE), fast ions play an essential role in confinement enhancement. GK simulations show a significant reduction of the thermal energy flux when the thermal ion fraction decreases and the main ion density gradient is reversed by the fast ions in FIRE mode. Optimization of 3D magnetic field techniques, including adaptive control and real-time machine learning control algorithm, enabled long-pulse operation and high-performance ELM-suppressed discharge. Symmetric multiple shattered pellet injections (SPIs) and real-time disruption event characterization and forecasting are being performed to mitigate and avoid the disruptions associated with high-performance, long-pulse ITER-like scenarios. Finally, the near-term research plan will be addressed with the actively cooled tungsten divertor, a major upgrade of the NBI and helicon current drive heating, and transition to a full metallic wall.

Published
2024
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35. Overview of T and D–T results in JET with ITER-like wall

Author

C.F. Maggi, D. Abate, N. Abid, P. Abreu, O. Adabonyan, M. Afzal, I. Ahmad, M. Akhtar, R. Albanese, S. Aleiferis, E. Alessi, P. Aleynikov, J. Alguacil, J. Alhage, M. Ali, H. Allen, M. Allinson, M. Alonzo, E. Alves, R. Ambrosino, E. Andersson Sundén, P. Andrew, M. Angelone, C. Angioni, I. Antoniou, L. Appel, C. Appelbee, C. Aramunde, M. Ariola, G. Arnoux, G. Artaserse, J.-F. Artaud, W. Arter, V. Artigues, F.J. Artola, A. Ash, O. Asztalos, D. Auld, F. Auriemma, Y. Austin, L. Avotina, J. Ayllón, E. Aymerich, A. Baciero, L. Bähner, F. Bairaktaris, I. Balboa, M. Balden, N. Balshaw, V.K. Bandaru, J. Banks, A. Banon Navarro, C. Barcellona, O. Bardsley, M. Barnes, R. Barnsley, M. Baruzzo, M. Bassan, A. Batista, P. Batistoni, L. Baumane, B. Bauvir, L. Baylor, C. Bearcroft, P. Beaumont, D. Beckett, A. Begolli, M. Beidler, N. Bekris, M. Beldishevski, E. Belli, F. Belli, S. Benkadda, J. Bentley, E. Bernard, J. Bernardo, M. Bernert, M. Berry, L. Bertalot, H. Betar, M. Beurskens, P.G. Bhat, S. Bickerton, J. Bielecki, T. Biewer, R. Bilato, P. Bílková, G. Birkenmeier, R. Bisson, J.P.S. Bizarro, P. Blatchford, A. Bleasdale, V. Bobkov, A. Boboc, A. Bock, G. Bodnar, P. Bohm, L. Bonalumi, N. Bonanomi, D. Bonfiglio, X. Bonnin, P. Bonofiglo, J. Booth, D. Borba, D. Borodin, I. Borodkina, T.O.S.J. Bosman, C. Bourdelle, M. Bowden, I. Božičević Mihalić, S.C. Bradnam, B. Breizman, S. Brezinsek, D. Brida, M. Brix, P. Brown, D. Brunetti, M. Buckley, J. Buermans, H. Bufferand, P. Buratti, A. Burckhart, A. Burgess, A. Buscarino, A. Busse, D. Butcher, G. Calabrò, L. Calacci, R. Calado, R. Canavan, B. Cannas, M. Cannon, M. Cappelli, S. Carcangiu, P. Card, A. Cardinali, S. Carli, P. Carman, D. Carnevale, B. Carvalho, I.S. Carvalho, P. Carvalho, I. Casiraghi, F.J. Casson, C. Castaldo, J.P. Catalan, N. Catarino, F. Causa, M. Cavedon, M. Cecconello, L. Ceelen, C.D. Challis, B. Chamberlain, R. Chandra, C.S. Chang, A. Chankin, B. Chapman, P. Chauhan, M. Chernyshova, A. Chiariello, G.-C. Chira, P. Chmielewski, A. Chomiczewska, L. Chone, J. Cieslik, G. Ciraolo, D. Ciric, J. Citrin, Ł. Ciupinski, R. Clarkson, M. Cleverly, P. Coates, V. Coccorese, R. Coelho, J.W. Coenen, I.H. Coffey, A. Colangeli, L. Colas, J. Collins, S. Conroy, C. Contré, N.J. Conway, D. Coombs, P. Cooper, S. Cooper, L. Cordaro, C. Corradino, Y. Corre, G. Corrigan, D. Coster, T. Craciunescu, S. Cramp, D. Craven, R. Craven, G. Croci, D. Croft, K. Crombé, T. Cronin, N. Cruz, A. Cufar, A. Cullen, A. Dal Molin, S. Dalley, P. David, A. Davies, J. Davies, S. Davies, G. Davis, K. Dawson, S. Dawson, I. Day, G. De Tommasi, J. Deane, M. Dearing, M. De Bock, J. Decker, R. Dejarnac, E. Delabie, E. de la Cal, E. de la Luna, D. Del Sarto, A. Dempsey, W. Deng, A. Dennett, G.L. Derks, G. De Temmerman, F. Devasagayam, P. de Vries, P. Devynck, A. di Siena, D. Dickinson, T. Dickson, M. Diez, P. Dinca, T. Dittmar, L. Dittrich, J. Dobrashian, T. Dochnal, A.J.H. Donné, W. Dorland, S. Dorling, S. Dormido-Canto, R. Dotse, D. Douai, S. Dowson, R. Doyle, M. Dreval, P. Drews, G. Drummond, Ph. Duckworth, H.G. Dudding, R. Dumont, P. Dumortier, D. Dunai, T. Dunatov, M. Dunne, I. Ďuran, F. Durodié, R. Dux, T. Eade, E. Eardley, J. Edwards, T. Eich, A. Eksaeva, H. El-Haroun, R.D. Ellis, G. Ellwood, C. Elsmore, S. Emery, G. Ericsson, B. Eriksson, F. Eriksson, J. Eriksson, L.G. Eriksson, S. Ertmer, G. Evans, S. Evans, E. Fable, D. Fagan, M. Faitsch, D. Fajardo Jimenez, M. Falessi, A. Fanni, T. Farmer, I. Farquhar, B. Faugeras, S. Fazinić, N. Fedorczak, K. Felker, R. Felton, H. Fernandes, D.R. Ferreira, J. Ferreira, G. Ferrò, J. Fessey, O. Février, O. Ficker, A.R. Field, A. Figueiredo, J. Figueiredo, A. Fil, N. Fil, P. Finburg, U. Fischer, G. Fishpool, L. Fittill, M. Fitzgerald, D. Flammini, J. Flanagan, S. Foley, N. Fonnesu, M. Fontana, J.M. Fontdecaba, L. Fortuna, E. Fortuna-Zalesna, M. Fortune, C. Fowler, P. Fox, O. Franklin, E. Fransson, L. Frassinetti, R. Fresa, D. Frigione, T. Fülöp, M. Furseman, S. Gabriellini, D. Gadariya, S. Gadgil, K. Gál, S. Galeani, A. Galkowski, D. Gallart, M. Gambrioli, T. Gans, J. Garcia, M. García-Muñoz, L. Garzotti, J. Gaspar, R. Gatto, P. Gaudio, D. Gear, T. Gebhart, S. Gee, M. Gelfusa, R. George, S.N. Gerasimov, R. Gerru, G. Gervasini, M. Gethins, Z. Ghani, M. Gherendi, P.-I. Gherghina, F. Ghezzi, L. Giacomelli, C. Gibson, L. Gil, M.R. Gilbert, A. Gillgren, E. Giovannozzi, C. Giroud, G. Giruzzi, J. Goff, V. Goloborodko, R. Gomes, J.-F. Gomez, B. Gonçalves, M. Goniche, J. Gonzalez-Martin, A. Goodyear, S. Gore, G. Gorini, T. Görler, N. Gotts, E. Gow, J.P. Graves, J. Green, H. Greuner, E. Grigore, F. Griph, W. Gromelski, M. Groth, C. Grove, R. Grove, N. Gupta, S. Hacquin, L. Hägg, A. Hakola, M. Halitovs, J. Hall, C.J. Ham, M. Hamed, M.R. Hardman, Y. Haresawa, G. Harrer, J.R. Harrison, D. Harting, D.R. Hatch, T. Haupt, J. Hawes, N.C. Hawkes, J. Hawkins, S. Hazael, J. Hearmon, P. Heesterman, P. Heinrich, M. Held, W. Helou, O. Hemming, S.S. Henderson, R. Henriques, R.B. Henriques, D. Hepple, J. Herfindal, G. Hermon, J.C. Hillesheim, K. Hizanidis, A. Hjalmarsson, A. Ho, J. Hobirk, O. Hoenen, C. Hogben, A. Hollingsworth, S. Hollis, E. Hollmann, M. Hölzl, M. Hook, M. Hoppe, J. Horáček, N. Horsten, A. Horton, L.D. Horton, L. Horvath, S. Hotchin, Z. Hu, Z. Huang, E. Hubenov, A. Huber, V. Huber, T. Huddleston, G.T.A. Huijsmans, Y. Husain, P. Huynh, A. Hynes, D. Iglesias, M.V. Iliasova, M. Imríšek, J. Ingleby, P. Innocente, V. Ioannou-Sougleridis, N. Isernia, I. Ivanova-Stanik, E. Ivings, S. Jachmich, T. Jackson, A.S. Jacobsen, P. Jacquet, H. Järleblad, A. Järvinen, F. Jaulmes, N. Jayasekera, F. Jenko, I. Jepu, E. Joffrin, T. Johnson, J. Johnston, C. Jones, E. Jones, G. Jones, L. Jones, T.T.C. Jones, A. Joyce, M. Juvonen, A. Kallenbach, P. Kalnina, D. Kalupin, P. Kanth, A. Kantor, A. Kappatou, O. Kardaun, J. Karhunen, E. Karsakos, Ye.O. Kazakov, V. Kazantzidis, D.L. Keeling, W. Kelly, M. Kempenaars, D. Kennedy, K. Khan, E. Khilkevich, C. Kiefer, H.-T. Kim, J. Kim, S.H. Kim, D.B. King, D.J. Kinna, V.G. Kiptily, A. Kirjasuo, K.K. Kirov, A. Kirschner, T. Kiviniemi, G. Kizane, C. Klepper, A. Klix, G. Kneale, M. Knight, P. Knight, R. Knights, S. Knipe, U. Knoche, M. Knolker, M. Kocan, F. Köchl, G. Kocsis, J.T.W. Koenders, Y. Kolesnichenko, Y. Kominis, M. Kong, B. Kool, V. Korovin, S.B. Korsholm, B. Kos, D. Kos, M. Koubiti, Y. Kovtun, E. Kowalska-Strzęciwilk, K. Koziol, Y. Krasikov, A. Krasilnikov, V. Krasilnikov, M. Kresina, A. Kreter, K. Krieger, A. Krivska, U. Kruezi, I. Książek, H. Kumpulainen, B. Kurzan, S. Kwak, O.J. Kwon, B. Labit, M. Lacquaniti, A. Lagoyannis, L. Laguardia, A. Laing, V. Laksharam, N. Lam, H.T. Lambertz, B. Lane, M. Langley, E. Lascas Neto, E. Łaszyńska, K.D. Lawson, A. Lazaros, E. Lazzaro, G. Learoyd, C. Lee, K. Lee, S. Leerink, T. Leeson, X. Lefebvre, H.J. Leggate, J. Lehmann, M. Lehnen, D. Leichtle, F. Leipold, I. Lengar, M. Lennholm, E. Leon Gutierrez, L.A. Leppin, E. Lerche, A. Lescinskis, S. Lesnoj, L. Lewin, J. Lewis, J. Likonen, Ch. Linsmeier, X. Litaudon, E. Litherland-Smith, F. Liu, T. Loarer, A. Loarte, R. Lobel, B. Lomanowski, P.J. Lomas, J. Lombardo, R. Lorenzini, S. Loreti, V.P. Loschiavo, M. Loughlin, T. Lowe, C. Lowry, T. Luce, R. Lucock, T. Luda Di Cortemiglia, M. Lungaroni, C.P. Lungu, T. Lunt, V. Lutsenko, B. Lyons, J. Macdonald, E. Macusova, R. Mäenpää, H. Maier, J. Mailloux, S. Makarov, P. Manas, A. Manning, P. Mantica, M.J. Mantsinen, J. Manyer, A. Manzanares, Ph. Maquet, M. Maraschek, G. Marceca, G. Marcer, C. Marchetto, O. Marchuk, A. Mariani, G. Mariano, M. Marin, A. Marin Roldan, M. Marinelli, T. Markovič, L. Marot, C. Marren, S. Marsden, S. Marsen, J. Marsh, R. Marshall, L. Martellucci, A.J. Martin, C. Martin, R. Martone, S. Maruyama, M. Maslov, M. Mattei, G.F. Matthews, D. Matveev, E. Matveeva, A. Mauriya, F. Maviglia, M. Mayer, M.-L. Mayoral, S. Mazzi, C. Mazzotta, R. McAdams, P.J. McCarthy, P. McCullen, R. McDermott, D.C. McDonald, D. McGuckin, V. McKay, L. McNamee, A. McShee, D. Mederick, M. Medland, S. Medley, K. Meghani, A.G. Meigs, S. Meitner, S. Menmuir, K. Mergia, S. Mianowski, P. Middleton, J. Mietelski, K. Mikszuta-Michalik, D. Milanesio, E. Milani, E. Militello-Asp, F. Militello, J. Milnes, A. Milocco, S. Minucci, I. Miron, J. Mitchell, J. Mlynář, V. Moiseenko, P. Monaghan, I. Monakhov, A. Montisci, S. Moon, R. Mooney, S. Moradi, R.B. Morales, L. Morgan, F. Moro, J. Morris, T. Mrowetz, L. Msero, S. Munot, A. Muñoz-Perez, M. Muraglia, A. Murari, A. Muraro, B. N’Konga, Y.S. Na, F. Nabais, R. Naish, F. Napoli, E. Nardon, V. Naulin, M.F.F. Nave, R. Neu, S. Ng, M. Nicassio, D. Nicolai, A.H. Nielsen, S.K. Nielsen, D. Nina, C. Noble, C.R. Nobs, M. Nocente, H. Nordman, S. Nowak, H. Nyström, J. O’Callaghan, M. O’Mullane, C. O’Neill, C. Olde, H.J.C. Oliver, R. Olney, J. Ongena, G.P. Orsitto, A. Osipov, R. Otin, N. Pace, L.W. Packer, E. Pajuste, D. Palade, J. Palgrave, O. Pan, N. Panadero, T. Pandya, E. Panontin, A. Papadopoulos, G. Papadopoulos, G. Papp, V.V. Parail, A. Parsloe, K. Paschalidis, M. Passeri, A. Patel, A. Pau, G. Pautasso, R. Pavlichenko, A. Pavone, E. Pawelec, C. Paz-Soldan, A. Peacock, M. Pearce, I.J. Pearson, E. Peluso, C. Penot, K. Pepperell, A. Perdas, T. Pereira, E. Perelli Cippo, C. Perez von Thun, D. Perry, P. Petersson, G. Petravich, N. Petrella, M. Peyman, L. Pigatto, M. Pillon, S. Pinches, G. Pintsuk, C. Piron, A. Pironti, F. Pisano, R. Pitts, U. Planck, N. Platt, V. Plyusnin, M. Podesta, G. Pokol, F.M. Poli, O.G. Pompilian, M. Poradzinski, M. Porkolab, C. Porosnicu, G. Poulipoulis, A.S. Poulsen, I. Predebon, A. Previti, D. Primetzhofer, G. Provatas, G. Pucella, P. Puglia, K. Purahoo, O. Putignano, T. Pütterich, A. Quercia, G. Radulescu, V. Radulovic, R. Ragona, M. Rainford, P. Raj, M. Rasinski, D. Rasmussen, J. Rasmussen, J.J. Rasmussen, A. Raso, G. Rattá, S. Ratynskaia, R. Rayaprolu, M. Rebai, A. Redl, D. Rees, D. Réfy, R. Reichle, H. Reimerdes, B.C.G. Reman, C. Reux, S. Reynolds, D. Rigamonti, E. Righi, F.G. Rimini, J. Risner, J.F. Rivero-Rodriguez, C.M. Roach, J. Roberts, R. Robins, S. Robinson, D. Robson, S. Rode, P. Rodrigues, P. Rodriguez-Fernandez, S. Romanelli, J. Romazanov, E. Rose, C. Rose-Innes, R. Rossi, S. Rowe, D. Rowlands, C. Rowley, M. Rubel, G. Rubinacci, G. Rubino, M. Rud, J. Ruiz Ruiz, F. Ryter, S. Saarelma, A. Sahlberg, M. Salewski, A. Salmi, R. Salmon, F. Salzedas, F. Sanchez, I. Sanders, D. Sandiford, F. Sanni, O. Sauter, P. Sauvan, G. Schettini, A. Shevelev, A.A. Schekochihin, K. Schmid, B.S. Schmidt, S. Schmuck, M. Schneider, P.A. Schneider, N. Schoonheere, R. Schramm, D. Scoon, S. Scully, M. Segato, J. Seidl, L. Senni, J. Seo, G. Sergienko, M. Sertoli, S.E. Sharapov, R. Sharma, A. Shaw, R. Shaw, H. Sheikh, U. Sheikh, N. Shi, P. Shigin, D. Shiraki, G. Sias, M. Siccinio, B. Sieglin, S.A. Silburn, A. Silva, C. Silva, J. Silva, D. Silvagni, D. Simfukwe, J. Simpson, P. Sirén, A. Sirinelli, H. Sjöstrand, N. Skinner, J. Slater, T. Smart, R.D. Smirnov, N. Smith, P. Smith, T. Smith, J. Snell, L. Snoj, E.R. Solano, V. Solokha, C. Sommariva, K. Soni, M. Sos, J. Sousa, C. Sozzi, T. Spelzini, F. Spineanu, L. Spolladore, D. Spong, C. Srinivasan, G. Staebler, A. Stagni, I. Stamatelatos, M.F. Stamp, Ž. Štancar, P.A. Staniec, G. Stankūnas, M. Stead, B. Stein-Lubrano, A. Stephen, J. Stephens, P. Stevenson, C. Steventon, M. Stojanov, D.A. St-Onge, P. Strand, S. Strikwerda, C.I. Stuart, S. Sturgeon, H.J. Sun, S. Surendran, W. Suttrop, J. Svensson, J. Svoboda, R. Sweeney, G. Szepesi, M. Szoke, T. Tadić, B. Tal, T. Tala, P. Tamain, K. Tanaka, W. Tang, G. Tardini, M. Tardocchi, D. Taylor, A.S. Teimane, G. Telesca, A. Teplukhina, A. Terra, D. Terranova, N. Terranova, D. Testa, B. Thomas, V.K. Thompson, A. Thorman, A.S. Thrysoe, W. Tierens, R.A. Tinguely, A. Tipton, H. Todd, M. Tomeš, A. Tookey, P. Tsavalas, D. Tskhakaya, L.-P. Turică, A. Turner, I. Turner, M. Turner, M.M. Turner, G. Tvalashvili, A. Tykhyy, S. Tyrrell, A. Uccello, V. Udintsev, A. Vadgama, D.F. Valcarcel, A. Valentini, M. Valisa, M. Vallar, M. Valovic, M. Van Berkel, K.L. van de Plassche, M. van Rossem, D. Van Eester, J. Varela, J. Varje, T. Vasilopoulou, G. Vayakis, M. Vecsei, J. Vega, M. Veis, P. Veis, S. Ventre, M. Veranda, G. Verdoolaege, C. Verona, G. Verona Rinati, E. Veshchev, N. Vianello, E. Viezzer, L. Vignitchouk, R. Vila, R. Villari, F. Villone, P. Vincenzi, A. Vitins, Z. Vizvary, M. Vlad, I. Voldiner, U. Von Toussaint, P. Vondráček, B. Wakeling, M. Walker, R. Walker, M. Walsh, R. Walton, E. Wang, F. Warren, R. Warren, J. Waterhouse, C. Watts, T. Webster, M. Weiland, H. Weisen, M. Weiszflog, N. Wendler, A. West, M. Wheatley, S. Whetham, A. Whitehead, D. Whittaker, A. Widdowson, S. Wiesen, M. Willensdorfer, J. Williams, I. Wilson, T. Wilson, M. Wischmeier, A. Withycombe, D. Witts, A. Wojcik-Gargula, E. Wolfrum, R. Wood, R. Woodley, R. Worrall, I. Wyss, T. Xu, D. Yadykin, Y. Yakovenko, Y. Yang, V. Yanovskiy, R. Yi, I. Young, R. Young, B. Zaar, R.J. Zabolockis, L. Zakharov, P. Zanca, A. Zarins, D. Zarzoso Fernandez, K.-D. Zastrow, Y. Zayachuk, M. Zerbini, W. Zhang, B. Zimmermann, M. Zlobinski, A. Zocco, V.K. Zotta, M. Zuin, W. Zwingmann, and I. Zychor

Subjects
magnetic fusion, JET-ILW, D–T, tritium, alpha particles, fusion prediction, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

In 2021 JET exploited its unique capabilities to operate with T and D–T fuel with an ITER-like Be/W wall (JET-ILW). This second major JET D–T campaign (DTE2), after DTE1 in 1997, represented the culmination of a series of JET enhancements—new fusion diagnostics, new T injection capabilities, refurbishment of the T plant, increased auxiliary heating, in-vessel calibration of 14 MeV neutron yield monitors—as well as significant advances in plasma theory and modelling in the fusion community. DTE2 was complemented by a sequence of isotope physics campaigns encompassing operation in pure tritium at high T-NBI power. Carefully conducted for safe operation with tritium, the new T and D–T experiments used 1 kg of T (vs 100 g in DTE1), yielding the most fusion reactor relevant D–T plasmas to date and expanding our understanding of isotopes and D–T mixture physics. Furthermore, since the JET T and DTE2 campaigns occurred almost 25 years after the last major D–T tokamak experiment, it was also a strategic goal of the European fusion programme to refresh operational experience of a nuclear tokamak to prepare staff for ITER operation. The key physics results of the JET T and DTE2 experiments, carried out within the EUROfusion JET1 work package, are reported in this paper. Progress in the technological exploitation of JET D–T operations, development and validation of nuclear codes, neutronic tools and techniques for ITER operations carried out by EUROfusion (started within the Horizon 2020 Framework Programme and continuing under the Horizon Europe FP) are reported in (Litaudon et al Nucl. Fusion accepted), while JET experience on T and D–T operations is presented in (King et al Nucl. Fusion submitted).

Published
2024
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36. Role of turbulent separatrix tangle in the improvement of the integrated pedestal and heat exhaust issue for stationary-operation tokamak fusion reactors

Author

C.S. Chang, S. Ku, R. Hager, J. Choi, D. Pugmire, S. Klasky, A. Loarte, and R.A Pitts

Subjects
tokamak, edge, divertor heat load, pedestal, gyrokinetic, separatrix, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

The magnetic separatrix surface is designed to provide the final and critical confinement to the hot stationary-operation core plasma in modern tokamak reactors in the absence of an external magnetic perturbation (MP) or transient magneto-hydrodynamic perturbation, while diverting the exhaust heat to divertor plates. All the stationary operational boundary plasma studies and reactor designs have been performed under this assumption. However, there has been a long-standing suspicion that a stationary-operation tokamak plasma even without external MPs or edge localized modes (ELMs) activities may not have a stable closed separatrix surface, especially near the magnetic X-point. Here, the first gyrokinetic numerical observation is reported that the divertor separatrix surface, due to homoclinic tangles caused by intrinsic electromagnetic turbulence, is not a stable closed surface in a stationary operation phase even without MPs or ELMs. Unlike the MP- or ELM-driven homoclinic tangles that could cause deleterious effects to core confinement or divertor plates, it is found that the micro-turbulence driven homoclinic tangles could connect the divertor plasma to the pedestal plasma in a constructive way by broadening the divertor heat-exhaust footprint and weakening the pedestal slope to the ELM-safe direction. Micro-turbulent homoclinic tangles can open a new research direction in understanding and controlling these two most troublesome and non-locally connected edge-plasma issues in a tokamak fusion reactor.

Published
2024
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37. Radiatively tamed divertor thermal loading in resonant magnetic perturbation (RMP)-driven, ELM-crash-suppressed plasmas

Author

Yongkyoon In, H.H. Lee, K. Kim, A. Loarte, I.H. Choi, J.Y. Heo, Y.S. Han, Wonho Choe, J. Hwang, and H. Shin

Subjects
edge-localized-modes (ELM), resonant magnetic perturbation (RMP), ELM-crash-suppression, divertor thermal loading, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Edge-localized-modes (ELMs) suppression by non-axisymmetric resonant-magnetic-perturbation (RMP) provides the way to reach high performance fusion plasmas without a threatening level of transient heat fluxes to the walls of fusion devices. The application of RMP, however, strongly modifies the heat flux pattern onto in-vessel components in contact with the plasma (especially the divertor) leading to local ‘hot spots’. Radiative dissipation by partially ionized species (impurities and deuterium) lowers the heat flux peaks on the walls but has been poorly compatible with such RMP-driven, ELM-crash-suppression. Here, we show how KSTAR has radiatively tamed divertor thermal loading down to more than a factor of 7 in the off-separatrix region without losing ELM-crash-suppression using ITER-like, three-row, RMP configurations, demonstrating its sustainment even in a partially detached plasma in the outer strike point, as required for ITER.

Published
2024
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38. Overview of recent experimental results on the EAST Tokamak

Author

X. Gong, on behalf of EAST Team and Collaborators, The EAST Team:, Yuntao Song, Baonian Wan, Jiangang Li, Yuanxi Wan, Xinchao Wu, Fukun Liu, Junling Chen, Jiansheng Hu, Guosheng Xu, Kun Lu, Xianzu Gong, Bingjia Xiao, Yu Wu, Xiang Gao, Damao Yao, Nong Xiang, Liqun Hu, Chundong Hu, Jiefeng Wu, Biao Shen, Ge Gao, Yiyun Huang, Liuwei Xu, Qiyong Zhang, Cheonho Bae, Bin Cao, Lei Cao, Jiafeng Chang, Dalong Chen, Ran Chen, Xiaojiao Chen, Yebin Chen, Yue Chen, Yunxin Cheng, Yong Cheng, Bojiang Ding, Fang Ding, Rui Ding, Shijun Du, Yanmin Duan, Jia Fu, Daming Gao, Wei Gao, Yongqi Gu, Bin Guo, Fei Guo, Yong Guo, Xiaofeng Han, Shiying He, Ailan Hu, Chang Hu, Guanghai Hu, Huaichuan Hu, Qingsheng Hu, Yanlan Hu, Zhenhua Hu, Juan Huang, Liansheng Huang, Ming Huang, Ronglin Huang, Xiang Ji, Hua Jia, Caichao Jiang, Yinxian Jie, Songqing Ju, Defeng Kong, Erzhong Li, Guoqiang Li, Jiahong Li, Junjun Li, Miaohui Li, Pan Li, Kedong Li, Shi Li, Yadong Li, Lizhen Liang, Yanchuan Liao, Shiyao Lin, Xin Lin, Bili Ling, Haiqing Liu, Huajun Liu, Jianwen Liu, Liang Liu, Shaocheng Liu, Sheng Liu, Wenbin Liu, Xiaoju Liu, Xiaoyan Liu, Yong Liu, Zhihong Liu, Zhimin Liu, Jianhua Lu, Zhengping Luo, Dengkui Ma, Huafeng Mao, Wendong Ma, Songtao Mao, Yuzhou Mao, Tingfeng Ming, Chao Pan, Chengkang Pan, Shengmin Pan, Jing Qian, Jinping Qian, Chengming Qin, Zhiyong Qiu, Qilong Ren, Zhicai Sheng, Shihua Song, Pengjun Sun, Xiaoyang Sun, Youwen Sun, Tian Tang, Ling Tao, Ang Ti, Baoguo Wang, Feng Wang, Fudi Wang, Huihui Wang, Jian Wang, Liang Wang, Linsen Wang, Mao Wang, Ping Wang, Xiaojie Wang, Shouxin Wang, Yating Wang, Yuehang Wang, Yong Wang, Zhengchu Wang, Jianglong Wei, Jing Wei, Xuechao Wei, Bin Wu, Dajun Wu, Hao Wu, Jinhua Wu, Xiangming Wu, Yibing Wu, Zege Wu, Weibin Xi, Tianyang Xia, Yezheng Xiao, Yahong Xie, Yuanlai Xie, Handong Xu, Liqing Xu, Weiye Xu, Ning Yan, Rong Yan, Jianhua Yang, Lei Yang, Qingxi Yang, Yao Yang, Zhongshi Yang, Min Yu, Yaowei Yu, Qiping Yuan, Shuai Yuan, Qing Zang, Bin Zhang, Jian Zhang, Jizong Zhang, Liyuan Zhang, Ling Zhang, Ruirui Zhang, Shoubiao Zhang, Tao Zhang, Wei Zhang, Xinjun Zhang, Xiuqing Zhang, Yang Zhang, Zuchao Zhang, Hailin Zhao, Lianmin Zhao, Guoqiang Zhong, Ruijie Zhou, Haishan Zhou, Tianhu Zhou, Yue Zhou, Dahuan Zhu, Haisheng Zhu, Ping Zhu, Zeying Zhu, Huidong Zhuang, Zibo Zhou, Zhiyong Zhou, Zhiwei Zhou, Guizhong Zuo, International and Domestic Collaborators:, Huishan Cai, Weixing Ding, Tao Lan, Adi Liu, Wandong Liu, Shaojie Wang, Minyou Ye, Yi Yu, Ge Zhuang, Wei Chen, Guangjiu Lei, Lin Nie, Min Xu, Huang Yuan, Nanhua Yao, Zhe Gao, Long Zeng, Tieshuan Fan, Liu Chen, Guoyong Fu, Zhiwei Ma, Zengmao Sheng, Yong Xiao, Xiaogang Wang, Zhongyong Chen, Yonghua Ding, Xiwei Hu, Zijiang Wang, Fangchuan Zhong, Hongbin Ding, Dezhen Wang, Zhengxiong Wang, Chenggang Jin, Xuemei Wu, Xiaofei Yang, Jianhua Zhang, Qingyuan Hu, Xi Yuan, Changqi Chen, Shuyi Gan, Xudi Wang, Congzhong Wu, Chongwei Zhang, Ting Zhang, Wu Zhu, Erhua Kong, Kaisong Wang, Chuanli Wang, Hongtao Yang, Lixiang Zhang, Yuhong Xu, Paul Anderson, Gheni Abla, Vincent Chan, John L. Doane, Andrea Garofalo, Punit Gohil, Chung Lih Hsieh, Ruey Hong, David Humphreys, Alan Walter Hyatt, Gary Jackson, Lang Lao, Yueqiang Liu, James Leuer, John Lohr, Mohamad Ali Mahdavi, Robert Olstad, Ben Penaflor, Ron Prater, David Piglowski, Michael Schaffe, Tim Scoville, Wayne Solomon, Mike Walker, Anders Welander, Manfred Bitter, Robert Budny, Robert A. Ellis, Nat Fisch, Rich Hawryluk, Kenneth W. Hill, Joel Hosea, Michael A. Jaworski, Egemen Kolemen, Rajesh Maingi, Dennis Mansfield, Dana M. Mastrovito, Jonathan Menard, Dennis Mueller, Novmir Pablant, Lane Roquemore, Filippo Scotti, Gary Taylor, Kevin Tritz, Randy Wilson, Michael Zarnstorff, Seung Gyou Baek, Beck Bill, Paul T. Bonoli, Robert Granetz, Ron Parker, Shunichi Shiraiwa, Josh Stillerman, Greg Wallace, Stephen Wukitch, Lihua Zhou, He Huang, Kenneth Gentle, Ken Liao, Perry Philippe, William L. Rowan, Linjin Zheng, Patrick H. Diamond, George R. Tynan, Nicolas Fedorczak, Peter Manz, Lei Zhao, David Brower, William W. Heidbrink, Yubao Zhu, Calvin W. Domier, Neville C. Luhmann, Chris Holcomb, Xueqiao Xu, Eric Wang, Max E. Fenstermarcher, Mickey Wade, Donald L. Hillis, Steve Meitner, Igor V. Vinyar, Vladimir Davydenko, Igor Shikhovtsev, Naoko Ashikawa, Kasahara Hiroshi, Katsumi Ida, Shinichiro Kado, Tomita Kawamura, Saito Kenji, Ryuhei Kumazawa, Ogawa Kunihiro, Isobe Mitsutaka, Shigeru Morita, Haruhisa Nakano, Masaki Osakabe, Mizuki Sakamoto, Yasuhiko Takeiri, Kazuo Toi, Katsuyoshi Tsumori, Nobuta Yuji, Masaya Hanada, Mitsuru Kikuchi, Atsushi Kojima, Kazuhiro Watanabe, Jean-Francois Artaud, Vincent Basiuk, F. Bouquey, B. Bremond, Laurent Colas, Joan Decker, D. Douai, Annika Ekedahl, Christel Fenzi, Eric Gauthier, Gerardo Giruzzi, Marc Goniche, Dominique Guilhem, Walid Helou, Julien Hillairet, Tuong Hoang, Philippe Huynh, Frederic Imbeaux, Xavier Litaudon, Roland Magne, Yves Peysson, K. Vueillie, Xiaolan Zou, Alberto Loarte, Richard Pitts, Tom Wauters, Franz Braun, R. Bilato, Volodymyr Bobkov, J.M. Noterdaeme, Qingquan Yu, Yunfeng Liang, Jonny Pearson, Michael Rack, Joseph Banks, John Fessey, Charles Monroe, Damian King, Stefan Schmuck, Hongjuan Sun, Paul Trimble, Tom Todd, Jun-Gyo Bak, Suk-Ho Hong, Sangong Lee, Bae Young Soon, Oh Byung Hoon, Chang Doo Hee, Lee Kwang Won, Luca Amicucci, Giuseppe Calabro, Silvio Ceccuzzi, Roberto Cesario, Flavio Crisanti, Edmondo Giovannozzi, Giuseppe Ramogida, Gianmaria De Tommasi, Angelo Antonio Tuccillo, Bruno Viola, Raffaele Albanese, Roberto Ambrosino, Lucio Barbato, Stefano Mastrostefano, Alfredo Pironti, Vincenzo Pericoli Ridolfini, Rory Scannell, Fabio Villone, Volker Naulin, Anders H. Nielsen, Roman Zagorsky, Sandor Zoletnik, Chijin Xiao, B. Madsen, M. Salewski, and Eugenio Schuster

Subjects
steady state long pulse, EAST tokamak, ITPA, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Since the last IAEA-FEC in 2021, significant progress on the development of long pulse steady state scenario and its related key physics and technologies have been achieved, including the reproducible 403 s long-pulse steady-state H-mode plasma with pure radio frequency (RF) power heating. A thousand-second time scale (∼1056 s) fully non-inductive plasma with high injected energy up to 1.73 GJ has also been achieved. The EAST operational regime of high β _P has been significantly extended ( H _98y2 > 1.3, β _P ∼ 4.0, β _N ∼ 2.4 and n _e / n _GW ∼ 1.0) using RF and neutral beam injection (NBI). The full edge localized mode suppression using the n = 4 resonant magnetic perturbations has been achieved in ITER-like standard type-I ELMy H-mode plasmas with q _95 ≈ 3.1 on EAST, extrapolating favorably to the ITER baseline scenario. The sustained large ELM control and stable partial detachment have been achieved with Ne seeding. The underlying physics of plasma-beta effect for error field penetration, where toroidal effect dominates, is disclosed by comparing the results in cylindrical theory and MARS-Q simulation in EAST. Breakdown and plasma initiation at low toroidal electric fields (

Published
2024
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39. Heuristic predictions of RMP configurations for ELM suppression in ITER burning plasmas and their impact on divertor performance

Author

H. Frerichs, J. van Blarcum, Y. Feng, L. Li, Y.Q. Liu, A. Loarte, J-K. Park, R.A. Pitts, O. Schmitz, and S.M. Yang

Subjects
resonant magnetic perturbations for ELM suppression, divertor detachment, 3D plasma boundary modeling, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

A subspace of resonant magnetic perturbation (RMP) configurations for edge localized mode (ELM) suppression is predicted for H-mode burning plasmas at 15 MA current and 5.3 T magnetic field in ITER. Perturbations to the core plasma can be reduced by a factor of 2 for equivalent edge stability proxies, while the perturbed plasma boundary geometry remains mostly resilient. The striated domain of perturbed field lines connecting from the main plasma (normalized poloidal flux $ {\lt} 1$ ) to the divertor targets is found to be significantly larger than the expected heat load width in the absence of RMPs. This facilitates heat load spreading with peak values at an acceptable level below $10 \, \mathrm{MW} \, \mathrm{m}^{-2}$ on the outer target already at moderate gas fueling and low Ne seeding for additional radiative dissipation of the $100 \, \mathrm{MW}$ of power into the scrape-off layer (SOL). On the inner target, however, re-attachment is predicted away from the equilibrium strike point due to increased upstream heat flux, higher downstream temperature and less efficient impurity radiation.

Published
2024
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40. Dynamic control of divertor heat flux during n = 4 resonant magnetic perturbation edge localized mode suppression by small variation of q 95 in EAST

Author

Hua Yang, Youwen Sun, Manni Jia, Alberto Loarte, Pengcheng Xie, Qun Ma, Xuemin Wu, Cheng Ye, Yueqiang Liu, Jiale Chen, Ruirong Liang, Zhendong Yang, Gaoting Chen, Bin Zhang, Qing Zang, Kaixuan Ye, and the EAST Team

Subjects
3D field modulation, divertor heat flux control, EAST, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Experiments at EAST demonstrate effective modulation of the stationary heat flux to the secondary lobes of the magnetic footprint induced by the resonant magnetic perturbations (RMPs) by slightly varying the equilibrium q _95 , consistent with prior numerical modeling. During the small q _95 variation, the edge localized mode control is well maintained, and the position of the secondary heat flux peak is effectively shifted, thus avoiding a specific location heat flux accumulation. As the divertor heat load is one of the significant concerns in tokamaks, these results provide a promising choice, varying magnetic equilibrium periodically to shift stationary heat load deposition position during static n = 4 ( n is the toroidal mode number) RMP condition, for further fusion devices. In this respect, the use of this technique for n = 4 RMPs is advantageous because the q _95 range that needs to be covered to spread the divertor heat load is reduced due to the smaller toroidal extent of the off-separatrix heat deposition zones compared to lower n ’s.

Published
2024
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41. FLIPEC, an ideal MHD free-boundary axisymmetric equilibrium solver in the presence of macroscopic flows

Author

G. F.-Torija Daza, J.M. Reynolds-Barredo, R. Sanchez, A. Loarte, and V. Tribaldos

Subjects
ideal MHD, plasma flows, free-boundary equilibrium, Grad–Shafranov–Bernoulli equations, iterative solvers, curvilinear coordinates, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

The most relevant features of FLIPEC (Free fLow Iterative Plasma Equilibrium Code) are presented. This new code iteratively calculates free-boundary, axisymmetric ideal MHD equilibria with arbitrary poloidal and toroidal plasma flows. FLIPEC is a mature code that has emerged from a complete overhaul of a previous version (F-Torija Daza 2022 et al Nucl. Fusion 62 126044). It uses a (inverse) curvilinear coordinate representation for the Grad–Shafranov–Bernoulli equation system, which allows FLIPEC to extend its free-boundary capabilities to arbitrary plasma shapes and removes many limitations with regards to the distance between plasma and external coils. Run-time stabilization of vertical modes has also been implemented by means of artificial feedback coils. Finally, active targeting schemes have also been included. These capabilities are illustrated on two very different cases: the ITER tokamak baseline configuration and a NSTX spherical tokamak equilibrium.

Published
2024
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42. Helium plasma operations on ASDEX Upgrade and JET in support of the non-nuclear phases of ITER

Author

A. Hakola, M. Balden, M. Baruzzo, R. Bisson, S. Brezinsek, T. Dittmar, D. Douai, M. Dunne, L. Garzotti, M. Groth, R. Henriques, L. Horvath, I. Jepu, E. Joffrin, A. Kappatou, D. Keeling, K. Krieger, B. Labit, M. Lennholm, J. Likonen, A. Loarte, P. Lomas, C. Lowry, M. Maslov, D. Matveev, R.A. Pitts, U. Plank, M. Rasinski, D. Ryan, S. Saarelma, S. Silburn, E.R. Solano, W. Suttrop, T. Tala, E. Tsitrone, N. Vianello, T. Wauters, A. Widdowson, M. Wischmeier, the EUROfusion Tokamak Exploitation Team, the ASDEX Upgrade Team, and JET Contributors

Subjects
helium plasma, H-mode, tungsten fuzz, erosion, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

For its initial operational phase, ITER has until recently considered using non-nuclear hydrogen (H) or helium (He) plasmas to keep nuclear activation at low levels. To this end, the Tokamak Exploitation Task Force of the EUROfusion Consortium carried out dedicated experimental campaigns in He on the ASDEX Upgrade (AUG) and JET tokamaks in 2022, with particular emphasis put on the ELMy H-mode operation and plasma-wall interaction processes as well as comparison to H or deuterium (D) plasmas. Both in pure He and mixed He + H plasmas, H-mode operation could be reached but more effort was needed to obtain a stable plasma scenario than in H or D. Even if the power threshold for the LH transition was lower in He, entering the type-I ELMy regime appeared to require equally much or even more heating power than in H. Suppression of ELMs by resonant magnetic perturbations was studied on AUG but was only possible in plasmas with a He content below 19%; the reason for this unexpected behaviour remains still unclear and various theoretical approaches are being pursued to properly understand the physics behind ELM suppression. The erosion rates of tungsten (W) plasma-facing components were an order of magnitude larger than what has been reported in hydrogenic plasmas, which can be attributed to the prominent role of He ^2+ ions in the plasma. For the first time, the formation of nanoscale structures (W fuzz) was unambiguously demonstrated in H-mode He plasmas on AUG. However, no direct evidence of fuzz creation on JET was obtained despite the main conditions for its occurrence being met. The reason could be a delicate balance between W erosion by ELMs, competition between the growth and annealing of the fuzz, and coverage of the surface with co-deposits.

Published
2024
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43. Ripple-induced neoclassical toroidal viscous torque in Augmented-First Plasma operation phase in ITER

Author

Yueqiang Liu, Xue Bai, Y. Gribov, F. Koechl, A. Loarte, S.D. Pinches, and L. Schmitz

Subjects
toroidal ripple, neoclassical toroidal viscosity, energetic particles, ITER, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

A systematic calculation is performed on the ripple-induced neoclassical toroidal viscous (NTV) torque for new ITER scenarios designed for the Augmented-First Plasma (A-FP) operation phase with the full tungsten wall, where the plasma-wall gap is varied in view of mitigating the impact of tungsten wall-plasma interactions. The torque calculation includes drift kinetic response of the plasma thermal and energetic particles to the n = 18 ( n is the toroidal harmonic number) ripple field. For the plasma scenario with ~45 cm plasma-wall gap at the outboard mid-plane and considering the corrected ripple level of 0.17% by the ferritic steel inserts, the computed net NTV torque acting on the plasma column is in the sub-Nm level. However, with decreasing the plasma-wall gap, the computed net NTV torque can reach a level comparable to that produced by the neutral-beam momentum injection in ITER. Ripple correction by ferritic inserts reduces the net torque by a factor of 3.3 for all the three A-FP scenarios considered. The $n\omega_d = l\omega_b$ (with ω _d and ω _b being the toroidal precession and bounce frequencies of trapped particles, respectively, and l an integer number) type of resonance-enhancement of the NTV torque, due to thermal particles, is found to be weak in ITER despite high- n of 18. The same also holds for the ITER 10 MA steady state scenario from the D-T operation phase, where the aforementioned resonance associated with fusion-born alphas is also included. The ripple-induced NTV torque is well below that produced by the resonant magnetic perturbation applied for controlling the type-I edge-localized mode in ITER.

Published
2024
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44. Quantification of locked mode instability triggered by a change in confinement

Author

M. Peterka, J. Seidl, T. Markovic, A. Loarte, N.C. Logan, J.-K. Park, P. Cahyna, J. Havlicek, M. Imrisek, L. Kripner, R. Panek, M. Sos, P. Bilkova, K. Bogar, P. Bohm, A. Casolari, Y. Gribov, O. Grover, P. Hacek, M. Hron, K. Kovarik, M. Tomes, D. Tskhakaya, J. Varju, P. Vondracek, V. Weinzettl, and the COMPASS Team

Subjects
tokamak, error field, L-H transition, disruption, locked mode, tearing mode seeding, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

This work presents the first analysis of the disruptive locked mode (LM) triggered by the dynamics of a confinement change. It shows that, under certain conditions, the LM threshold during the transient is significantly lower than expected from steady states. We investigate the sensitivity to a controlled n = 1 error field (EF) activated prior to the L-H transition in the COMPASS tokamak, at q _95 ∼ 3, β _N ∼ 1, and using EF coils on the high-field side of the vessel. A threshold for EF penetration subsequent to the L-H transition is identified, which shows no significant trend with density or applied torque, and is an apparent consequence of the reduced intrinsic rotation of the 2/1 mode during this transient phase. This finding challenges the assumption made in theoretical and empirical works that natural mode rotation can be predicted by global plasma parameters and urges against using any parametric EF penetration scaling derived from steady-state experiments to define the EF correction strategy in the entire discharge. Furthermore, even at EFs below the identified penetration threshold, disruptive locking of sawtooth-seeded 2/1 tearing modes is observed after about 30% of L-H transitions without external torque.

Published
2024
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46. Improved rainfall and temperature satellite dataset in areas with scarce weather stations data: case study in Ancash, Peru

Author

Eduardo E. Villavicencio, Katy D. Medina, Edwin A. Loarte, and Hairo A. León

Subjects
trmm, gpm, merra-2, weather stations, ancash, Geography (General), G1-922
Abstract

Rainfall and temperature variables play an important role in understanding meteorology at global and regional scales. However, the availability of meteorological information in areas of complex topography is difficult, as the density of weather stations is often very low. In this study, we focused on improving existing satellite products for these areas, using Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Measurement (GPM) data for rainfall and Modern Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2) data for air temperature. Our objective was to propose a model that improves the accuracy and correlation of satellite data with observed data on a monthly scale during 2012-2017. The improvement of rainfall satellite data was performed using 4 regions: region 1 Santa (R1Sn), region 2 Marañón (R2Mr), region 3 Pativilca (R3Pt) and region 4 Pacific (R4Pc). For temperature, a model based on the use of the slope obtained between temperature and altitude data was used. In addition, the reliability of the TRMM, GPM and MERRA-2 data was analyzed based on the ratio of the mean square error, PBIAS, Nash-Sutcliffe efficiency (NSE) and correlation coefficient. The final products obtained from the model for temperature are reliable with R2 ranging from 0.72 to 0.95 for the months of February and August respectively, while the improved rainfall products obtained are shown to be acceptable (NSE≥0.6) for the regions R1Sn, R2Mr and R3Pt. However, in R4Pc it is unacceptable (NSE

Published
2022
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47. A methodology for the selection and characterization of riboflavin-overproducing Weissella cibaria strains after treatment with roseoflavin

Author

Iñaki Diez-Ozaeta, Lucía Martín-Loarte, Mari Luz Mohedano, Mercedes Tamame, José Ángel Ruiz-Masó, Gloria del Solar, María Teresa Dueñas, and Paloma López

Subjects
Weissella cibaria, lactic acid bacteria, vitamin B2 (riboflavin), FMN riboswitch, roseoflavin, riboflavin overproducing bacteria, Microbiology, QR1-502
Abstract

Fermentative processes by lactic acid bacteria can produce metabolites of interest to the health and food industries. Two examples are the production of B-group vitamins, and of prebiotic and immunomodulatory dextran-type exopolysaccharides. In this study, three riboflavin- and dextran-producing Weissella cibaria strains (BAL3C-5, BAL3C-7 and BAL3C-22) were used to develop a new method for selection and isolation of spontaneous riboflavin-overproducing W. cibaria mutants. This method was based on the selection of strains resistant to roseoflavin. The DNA sequencing of the FMN riboswitch of bacterial cell populations treated with various roseoflavin concentrations, revealed the existence of at least 10 spontaneous and random point mutations at this location. Folding and analysis of the mutated FMN riboswitches with the RNA fold program predicted that these mutations could result in a deregulation of the rib operon expression. When the roseoflavin-treated cultures were plated on medium supporting dextran synthesis, the most promising mutants were identified by the yellow color of their mucous colonies, exhibiting a ropy phenotype. After their isolation and recovery in liquid medium, the evaluation of their riboflavin production revealed that the mutant strains synthesized a wide range of riboflavin levels (from 0.80 to 6.50 mg/L) above the wild-type level (0.15 mg/L). Thus, this was a reliable method to select spontaneous riboflavin-overproducing and dextran-producing strains of W. cibaria. This species has not yet been used as a starter or adjunct culture, but this study reinforces the potential that it has for the food and health industry for the production of functional foods or as a probiotic. Furthermore, analysis of the influence of FMN present in the growth medium, on rib mRNA and riboflavin levels, revealed which mutant strains produce riboflavin without flavin regulation. Moreover, the BAL3C-5 C120T mutant was identified as the highest riboflavin-overproducer. Determination of its chromosomal DNA sequence and that of BAL3C-5, revealed a total identity between the 2 strains except for the C120T mutation at the FMN riboswitch. To our knowledge, this work is the first demonstration that only a single alteration in the genome of a lactic acid bacteria is required for a riboflavin-overproducing phenotype.

Published
2023
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48. Gyrokinetic projection of the divertor heat-flux width from present tokamaks to ITER

Author

Chang, C. S., Ku, S., Loarte, A., Parail, V., Köchl, F., Romanelli, M., Maingi, R., Ahn, J. -W., Gray, T., Hughes, J., LaBombard, B., Leonard, T., Makowski, M., and Terry, J.

Subjects
Physics - Plasma Physics
Abstract

The XGC1 edge gyrokinetic code is used for a high fidelity prediction for the width of the heat-flux to divertor plates in attached plasma condition. The simulation results are validated against the empirical scaling $\lambda_q \propto B_P^{-\gamma}$ obtained from present tokamak devices, where $\lambda_q$ is the divertor heat-flux width mapped to the outboard midplane and $\gamma_q=1.19$ as defined by T. Eich et al. [Nucl. Fusion 53 (2013) 093031], and $B_P$ is the magnitude of the poloidal magnetic field at outboard midplane separatrix surface. This empirical scaling predicts $\lambda_q \leq 1mm$ when extrapolated to ITER, which would require operation with very high separatrix densities $(n_{sep}/n_{Greenwald} > 0.6)$ in the Q=10 scenario to achieve semi-detached plasma operation and high radiative fractions leading to acceptable divertor power fluxes. XGC1 predicts, however, that $\lambda_q$ for ITER is over 5 mm, suggesting that operation in the ITER Q=10 scenario with acceptable divertor power loads could be obtained over a wider range of plasma separatrix densities and radiative fractions. The physics reason behind this difference is, according to the XGC1 results, that while the ion magnetic drift contribution to the divertor heat-flux width is wider in the present tokamaks, the turbulent electron contribution is wider in ITER. A high current C-Mod discharge is found to be in a mixed regime: While the heat-flux width by the ion neoclassical magnetic drift is still wider than the turbulent electron heat-flux width, the heat-flux magnitude is dominated by the narrower electron heat-flux., Comment: Submitted to Nuclear Fusion

Published
2017
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49. Critical congenital heart disease detection in the ANDES: Challenges and opportunities

Author

Kelly Meza, Tania Vasquez-Loarte, J. Franco Rodriguez-Alarcon, Oscar San Roman, Jose Rojas-Camayo, Christian R. Mejia, Monica Medina, Henry A. Zapata, Annamarie Saarinen, and Katia Bravo-Jaimes

Subjects
Congenital heart disease, High altitude, Andean populations, Diseases of the circulatory (Cardiovascular) system, RC666-701
Abstract

Critical congenital heart disease (CCHD) represents a challenging problem in global health equity due to the need for specialized surgical or transcatheter intervention within the first year of life. CCHD screening using pulse oximetry (POS) has led to significant improvements in mortality due to early referral and intervention. Andean America represents one of the few regions in the world with increasing CHD deaths and variable POS implementation. In this manuscript, we review the current state of CCHD in Andean America, the challenges and opportunities for developing new POS algorithms that account for high-altitude physiology, data on regional cost-effectiveness supporting POS implementation and outline future directions to achieve equity in CHD care in this region.

Published
2022
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