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1. Improvement of lower hybrid current drive systems for high-power and long-pulse operation on EAST

Author

M. Wang, L. Liu, L.M. Zhao, M.H. Li, W.D. Ma, H.C. Hu, Z.G. Wu, J.Q. Feng, Y. Yang, L. Zhu, M. Chen, T.A. Zhou, H. Jia, J. Zhang, L. Cao, L. Zhang, R.R. Liang, B.J. Ding, X.J. Zhang, J.F. Shan, F.K. Liu, A. Ekedahl, M. Goniche, J. Hillairet, and L. Delpech

Subjects
Lower hybrid current drive, Hot spots, Fast electrons, Long-pulse operation, Tokamak, Nuclear engineering. Atomic power, TK9001-9401
Abstract

Aiming at high-power and long-pulse operation up to 1000 s, some improvements have been made for both 2.45 GHz and 4.6 GHz lower hybrid (LH) systems during the recent 5 years. At first, the guard limiters of the LH antennas with graphite tiles were upgraded to tungsten, the most promising material for plasma facing components in nuclear fusion devices. These new guard limiters can operate at a peak power density of 12.9 MW/m2. Strong hot spots were usually observed on the old graphite limiters when 4.6 GHz system operated with power >2.0 MW [B. N. Wan et al., Nucl. Fusion 57 (2017) 102019], leading to a reduction of the maximum power capability. With the new limiters, 4.6 GHz LH system, the main current drive (CD) and electron heating tool for EAST, can be operated with power >2.5 MW routinely. Long-pulse operation up to 100 s with 4.6 GHz LH power of 2.4 MW was achieved in 2021 and the maximal temperature on the guard limiters measured by an infrared (IR) camera was about 540 °C, much below the permissible value of tungsten material (∼1200 °C). A discharge with a duration of 1056 s was achieved and the 4.6 GHz LH energy injected into the plasma was up to 1.05 GJ. Secondly, the fully-active-multijunction (FAM) launcher of 2.45 GHz system was upgraded to a passive-active-multijunction (PAM), for which the density of optimum coupling was relatively low (below the cut-off value). Good coupling with reflection coefficient ∼3% has been achieved with plasma-antenna distance up to 11 cm for the new PAM. Finally, in order to eliminate the effect of ion cyclotron range of frequencies (ICRF) wave on 4.6 GHz LH wave coupling, the location of the ICRF launcher was changed to a port that is located 157.5° toroidally from the 4.6 GHz LH system and is not magnetically connected.

Published
2022
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2. Model-predictive kinetic control with data-driven models on EAST

Author

D. Moreau, S. Wang, J.P. Qian, Q. Yuan, Y. Huang, Y. Li, S. Ding, H. Du, X. Gong, M. Li, H. Liu, Z. Luo, L. Zeng, E. Olofsson, B. Sammuli, J.F. Artaud, A. Ekedahl, and E. Witrant

Subjects
tokamaks, plasma control, kinetic control, profile control, model-predictive control, two-time-scale control, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

In this work, model-predictive control (MPC) was combined for the first time with singular perturbation theory, and an original plasma kinetic control method based on extremely simple data-driven models and a two-time-scale MPC algorithm has been developed. A comprehensive review is presented in this paper. Slow and fast semi-empirical models are identified from data, by considering the fast kinetic plasma dynamics as a singular perturbation of a quasi-static equilibrium, which itself is governed, on the slow time scale, by the flux diffusion equation. This control technique takes advantage of the large ratio between the time scales involved in magnetic and kinetic plasma transport. It is applied here to the simultaneous control of the safety factor profile, q (𝑥), and of several kinetic variables, such as the poloidal beta parameter, β _p , and the internal inductance parameter, l _i , on the EAST tokamak. In the experiments, the available control actuators were lower hybrid current drive (LHCD) and co-current neutral beam injection (NBI) from different sources. Ion cyclotron resonant heating (ICRH) and electron cyclotron resonant heating (ECRH) are used as additional actuators in control simulations. In the controller design, an observer provides, in real time, an estimate of the system states and of the mismatch between measured and predicted outputs, which ensures robustness to model errors and offset-free control. Based on the observer information, the controller predicts the behavior of the system over a given time horizon and computes the optimal actuation by solving a quadratic programming optimization problem that takes the actuator constraints into account. A number of control applications are described in the paper, either in nonlinear simulations with EAST-like parameters or in real experiments on EAST. The simulations were performed with a fast plasma simulator (METIS) using either two control actuators (LHCD and ICRH) in a low density scenario, or up to four actuators at higher density: LHCD, ECRH, and two NBI systems driven in a on/off pulse-width-modulation (PWM) mode, with different injection angles. The control models are identified with the prediction-error method, using datasets obtained from open loop simulations in which the actuators are modulated with pseudo-random binary sequences. The simulations with two actuators show that various q (𝑥) profiles and β _p waveforms can be tracked without offset, within times that are consistent with the resistive and thermal diffusion time scales, respectively. In simulations with four actuators, simultaneous tracking of time-dependent targets is shown for q (𝑥) at two normalized radii, 𝑥 = 0 and 𝑥 = 0.4, and for β _p . Due to the inherent mismatch between the optimal NBI power request and the delivered PWM power, the kinetic controller performs with reduced accuracy compared with simulations that do not use the NBI/PWM actuators. The first experimental tests using this new control algorithm were performed on EAST when the only available actuator was the LHCD system at 4.6 GHz. The algorithm was thus used in its simplest single-input-single-output version to track time-dependent targets for the central safety factor, q _0 , or for β _p . In the closed loop control experiments, the q _0 targets were tracked in about one second, consistently with the plasma resistive time constant. Excellent tracking of a piecewise linear β _p target waveform was also achieved. When the NBI system became controllable in real time by the EAST plasma control system, new experiments were dedicated to multiple-input-multiple-output MPC control with three actuators: LHCD and two NBI actuators using the PWM algorithm. Given that the minimum time allowed between NBI on/off switching was 0.1 s, i.e. larger than the characteristic time of the fast plasma dynamics, a reduced version of the MPC controller based only on the slow model was used. Various controller configurations were tested during a single experimental session, with up to three controlled variables chosen among q _0 = q ( 𝑥 = 0), q _1 = q ( 𝑥 = 0.5), β _p and l _i . The main difficulty encountered during this session was the unavailability of the full baseline ICRH and ECRH powers that were used in the reference scenario, and from which the plasma model was identified. This often led to the saturation of one or several actuators, which prevented some targets selected in advance from being accessible. Nevertheless, in cases that were free from actuator saturation, q _0 and q _1 targets were successfully reached, in a time that is consistent with the resistive diffusion time of the model and with small oscillations that are characteristic of the PWM operation of the neutral beams. During the simultaneous control of q _0 and β _p , the ICRH power was too low and, in addition, the plasma density was much larger than the reference one. The q _0 targets were not accessible in this high-density/low-power case, but β _p control was successful. Finally, the simultaneous control of q _0 and l _i was satisfactory and, during the simultaneous control of, q _0 , β _p and l _i , the tracking of β _p and l _i was satisfactory but q _0 was too large due to the lack of ICRH power and to NBI saturation. In conclusion, the extensive nonlinear simulations described in this paper have demonstrated the relevance of combining MPC, data-driven models and singular perturbation methods for plasma kinetic control. This technique was also assessed experimentally on EAST, although some tests were perturbed by undesired parameter changes with respect to the reference scenario.

Published
2024
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3. 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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4. Calorimetry measurement for energy balance and energy distribution in WEST for L-mode plasmas

Author

J. Gaspar, J. Gerardin, Y. Corre, J. Daumas, N. Fedorczak, V. Lamaison, C. Bourdelle, G. Ciraolo, A. Ekedahl, A. Gallo, N. Rivals, E. Tsitrone, and the WEST Team

Subjects
calorimetry measurement, energy balance, heat load measurement, WEST tokamak, power exhaust, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

This paper presents the energy balance of 602 pulses from four different experimental campaigns for the WEST tokamak. Different magnetic configurations have been studied, with lower single null (LSN) and upper single null (USN) configuration with deuterium or helium plasmas. The energy balance is closed with an imbalance of about 5% of the total injected energy for most of the campaigns and for different magnetic configurations. The distribution over the whole machine is shown, with the outer first wall receiving most of the energy due to its large surface area with about 30% of the total heat load, and the divertor with 25% due to the heat loads deposited by the convected power in the scrape-off layer (SOL). Finally, the tomography inversion of the bolometry measurement allows us to disentangle the contribution of the radiated and convected power in the energy absorbed by each type of plasma-facing component. We show that in the USN configuration about 63% of the available energy in the SOL is deposited in the upper divertor (UDIV) through convected heat loads, while in LSN this value is spread over the lower divertor with 45% and the baffle and UDIV with about 10% for both.

Published
2024
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5. Design and analysis of a PAM launcher at 4.6 GHz for a new LHCD system on EAST

Author

M.H. Li, L. Liu, Y. Yang, L.M. Zhao, W.D. Ma, T.A. Zhou, M. Wang, W.Q. Ma, C.B. Wu, B.J. Ding, H. Jia, Z.G. Wu, W.Y. Zhou, X.L. Li, L. Yin, J. Hillairet, Y. Savoye-Peysson, M. Goniche, A. Ekedahl, and X.Z. Gong

Subjects
LHCD, PAM launcher, coupling performance, current drive efficiency, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

To improve the Current Drive (CD) capability in long-pulse (up to ∼1000 s) H-mode operation, it has been decided to develop a new Lower Hybrid Current Drive system at 4.6 GHz with an active cooling Passive Active Multijunction (PAM) launcher on EAST. In this paper, both the radio frequency (RF) and the physical properties of this PAM are studied numerically. The same nominal parallel refractive index ( N _|| = k _|| c/ ω , where k _|| is the parallel wavenumber, c the velocity of light, and ω the wave angular frequency) of 2.04 as the existing 4.6 GHz Full Active Multijunction (FAM) is chosen. Ray-tracing calculations indicate that good accessibility could be achieved when the LH waves radiate with this nominal N _|| in typical long-pulse H-mode plasmas. The coupling performance in terms of power reflection coefficient ( R _C ), power spectrum, maximum electric field, power directivity ( D _P ) and global CD capability is evaluated with the ALOHA code based on the linear coupling theory. Good coupling performance with averaged R _C ⩽ 1% and D _P ∼ 70% could be expected with the density ( n _e ) in front of the PAM close to the cut-off value ( n _e_co ). The simulated R _C remains below 6.5% over a wide density range 0.5 ⩽ n _e / n _e_co ⩽ 10, which is similar to the plasma edge conditions produced by Edge Localized Mode activity. A detailed comparison with the existing 4.6 GHz FAM launcher is also performed.

Published
2024
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6. Overview of the EUROfusion Tokamak Exploitation programme in support of ITER and DEMO

Author

E. Joffrin, M. Wischmeier, M. Baruzzo, A. Hakola, A. Kappatou, D. Keeling, B. Labit, E. Tsitrone, N. Vianello, the ASDEX Upgrade Team, JET Contributors, the MAST-U Team, the TCV Team, the WEST Team, the EUROfusion Tokamak Exploitation Team:, D. Abate, J. Adamek, M. Agostini, C. Albert, F.C.P. Albert Devasagayam, S. Aleiferis, E. Alessi, J. Alhage, S. Allan, J. Allcock, M. Alonzo, G. Anastasiou, E. Andersson Sunden, C. Angioni, Y. Anquetin, L. Appel, G.M. Apruzzese, M. Ariola, C. Arnas, J.F. Artaud, W. Arter, O. Asztalos, L. Aucone, M.H. Aumeunier, F. Auriemma, J. Ayllon, E. Aymerich, A. Baciero, F. Bagnato, L. Bähner, F. Bairaktaris, P. Balázs, L. Balbinot, I. Balboa, M. Balden, A. Balestri, M. Baquero Ruiz, T. Barberis, C. Barcellona, O. Bardsley, S. Benkadda, T. Bensadon, E. Bernard, M. Bernert, H. Betar, R. Bianchetti Morales, J. Bielecki, R. Bilato, P. Bilkova, W. Bin, G. Birkenmeier, R. Bisson, P. Blanchard, A. Bleasdale, V. Bobkov, A. Boboc, A. Bock, K. Bogar, P. Bohm, T. Bolzonella, F. Bombarda, N. Bonanomi, L. Boncagni, D. Bonfiglio, R. Bonifetto, M. Bonotto, D. Borodin, I. Borodkina, T.O.S.J. Bosman, C. Bourdelle, C. Bowman, S. Brezinsek, D. Brida, F. Brochard, R. Brunet, D. Brunetti, V. Bruno, R. Buchholz, J. Buermans, H. Bufferand, P. Buratti, A. Burckhart, J. Cai, R. Calado, J. Caloud, S. Cancelli, F. Cani, B. Cannas, M. Cappelli, S. Carcangiu, A. Cardinali, S. Carli, D. Carnevale, M. Carole, M. Carpita, D. Carralero, F. Caruggi, I.S. Carvalho, I. Casiraghi, A. Casolari, F.J. Casson, C. Castaldo, A. Cathey, F. Causa, J. Cavalier, M. Cavedon, J. Cazabonne, M. Cecconello, L. Ceelen, A. Celora, J. Cerovsky, C.D. Challis, R. Chandra, A. Chankin, B. Chapman, H. Chen, M. Chernyshova, A.G. Chiariello, P. Chmielewski, A. Chomiczewska, C. Cianfarani, G. Ciraolo, J. Citrin, F. Clairet, S. Coda, R. Coelho, J.W. Coenen, I.H. Coffey, C. Colandrea, L. Colas, S. Conroy, C. Contre, N.J. Conway, L. Cordaro, Y. Corre, D. Costa, S. Costea, D. Coster, X. Courtois, C. Cowley, T. Craciunescu, G. Croci, A.M. Croitoru, K. Crombe, D.J. Cruz Zabala, G. Cseh, T. Czarski, A. Da Ros, A. Dal Molin, M. Dalla Rosa, Y. Damizia, O. D’Arcangelo, P. David, M. De Angeli, E. De la Cal, E. De La Luna, G. De Tommasi, J. Decker, R. Dejarnac, D. Del Sarto, G. Derks, C. Desgranges, P. Devynck, S. Di Genova, L.E. di Grazia, A. Di Siena, M. Dicorato, M. Diez, M. Dimitrova, T. Dittmar, L. Dittrich, J.J. Domínguez Palacios Durán, P. Donnel, D. Douai, S. Dowson, S. Doyle, M. Dreval, P. Drews, L. Dubus, R. Dumont, D. Dunai, M. Dunne, A. Durif, F. Durodie, G. Durr Legoupil Nicoud, B. Duval, R. Dux, T. Eich, A. Ekedahl, S. Elmore, G. Ericsson, J. Eriksson, B. Eriksson, F. Eriksson, S. Ertmer, A. Escarguel, B. Esposito, T. Estrada, E. Fable, M. Faitsch, N. Fakhrayi Mofrad, A. Fanni, T. Farley, M. Farník, N. Fedorczak, F. Felici, X. Feng, J. Ferreira, D. Ferreira, N. Ferron, O. Fevrier, O. Ficker, A.R. Field, A. Figueiredo, N. Fil, D. Fiorucci, M. Firdaouss, R. Fischer, M. Fitzgerald, M. Flebbe, M. Fontana, J. Fontdecaba Climent, A. Frank, E. Fransson, L. Frassinetti, D. Frigione, S. Futatani, R. Futtersack, S. Gabriellini, D. Gadariya, D. Galassi, K. Galazka, J. Galdon, S. Galeani, D. Gallart, A. Gallo, C. Galperti, M. Gambrioli, S. Garavaglia, J. Garcia, M. Garcia Munoz, J. Gardarein, L. Garzotti, J. Gaspar, R. Gatto, P. Gaudio, M. Gelfusa, J. Gerardin, S.N. Gerasimov, R. Gerru Miguelanez, G. Gervasini, Z. Ghani, F.M. Ghezzi, G. Ghillardi, L. Giannone, S. Gibson, L. Gil, A. Gillgren, E. Giovannozzi, C. Giroud, G. Giruzzi, T. Gleiter, M. Gobbin, V. Goloborodko, A. González Ganzábal, T. Goodman, V. Gopakumar, G. Gorini, T. Görler, S. Gorno, G. Granucci, D. Greenhouse, G. Grenfell, M. Griener, W. Gromelski, M. Groth, O. Grover, M. Gruca, A. Gude, C. Guillemaut, R. Guirlet, J. Gunn, T. Gyergyek, L. Hagg, J. Hall, C.J. Ham, M. Hamed, T. Happel, G. Harrer, J. Harrison, D. Harting, N.C. Hawkes, P. Heinrich, S. Henderson, P. Hennequin, R. Henriques, S. Heuraux, J. Hidalgo Salaverri, J. Hillairet, J.C. Hillesheim, A. Hjalmarsson, A. Ho, J. Hobirk, E. Hodille, M. Hölzl, M. Hoppe, J. Horacek, N. Horsten, L. Horvath, M. Houry, K. Hromasova, J. Huang, Z. Huang, A. Huber, E. Huett, P. Huynh, A. Iantchenko, M. Imrisek, P. Innocente, C. Ionita Schrittwieser, H. Isliker, P. Ivanova, I. Ivanova Stanik, M. Jablczynska, S. Jachmich, A.S. Jacobsen, P. Jacquet, A. Jansen van Vuuren, A. Jardin, H. Järleblad, A. Järvinen, F. Jaulmes, T. Jensen, I. Jepu, S. Jessica, T. Johnson, A. Juven, J. Kalis, J. Karhunen, R. Karimov, A.N. Karpushov, S. Kasilov, Y. Kazakov, P.V. Kazantzidis, W. Kernbichler, HT. Kim, D.B. King, V.G. Kiptily, A. Kirjasuo, K.K. Kirov, A. Kirschner, A. Kit, T. Kiviniemi, F. Kjær, E. Klinkby, A. Knieps, U. Knoche, M. Kochan, F. Köchl, G. Kocsis, J.T.W. Koenders, L. Kogan, Y. Kolesnichenko, Y. Kominis, M. Komm, M. Kong, B. Kool, S.B. Korsholm, D. Kos, M. Koubiti, J. Kovacic, Y. Kovtun, E. Kowalska Strzeciwilk, K. Koziol, M. Kozulia, A. Krämer Flecken, A. Kreter, K. Krieger, U. Kruezi, O. Krutkin, O. Kudlacek, U. Kumar, H. Kumpulainen, M.H. Kushoro, R. Kwiatkowski, M. La Matina, M. Lacquaniti, L. Laguardia, P. Lainer, P. Lang, M. Larsen, E. Laszynska, K.D. Lawson, A. Lazaros, E. Lazzaro, M.Y.K. Lee, S. Leerink, M. Lehnen, M. Lennholm, E. Lerche, Y. Liang, A. Lier, J. Likonen, O. Linder, B. Lipschultz, A. Listopad, X. Litaudon, E. Litherland Smith, D. Liuzza, T. Loarer, P.J. Lomas, J. Lombardo, N. Lonigro, R. Lorenzini, C. Lowry, T. Luda di Cortemiglia, A. Ludvig Osipov, T. Lunt, V. Lutsenko, E. Macusova, R. Mäenpää, P. Maget, C.F. Maggi, J. Mailloux, S. Makarov, K. Malinowski, P. Manas, A. Mancini, D. Mancini, P. Mantica, M. Mantsinen, J. Manyer, M. Maraschek, G. Marceca, G. Marcer, C. Marchetto, S. Marchioni, A. Mariani, M. Marin, M. Markl, T. Markovic, D. Marocco, S. Marsden, L. Martellucci, P. Martin, C. Martin, F. Martinelli, L. Martinelli, J.R. Martin Solis, R. Martone, M. Maslov, R. Masocco, M. Mattei, G.F. Matthews, D. Matveev, E. Matveeva, M.L. Mayoral, D. Mazon, S. Mazzi, C. Mazzotta, G. McArdle, R. McDermott, K. McKay, A.G. Meigs, C. Meineri, A. Mele, V. Menkovski, S. Menmuir, A. Merle, H. Meyer, K. Mikszuta Michalik, D. Milanesio, F. Militello, A. Milocco, I.G. Miron, J. Mitchell, R. Mitteau, V. Mitterauer, J. Mlynar, V. Moiseenko, P. Molna, F. Mombelli, C. Monti, A. Montisci, J. Morales, P. Moreau, J.M. Moret, A. Moro, D. Moulton, P. Mulholland, M. Muraglia, A. Murari, A. Muraro, P. Muscente, D. Mykytchuk, F. Nabais, Y. Nakeva, F. Napoli, E. Nardon, M.F. Nave, R.D. Nem, A. Nielsen, S.K. Nielsen, M. Nocente, R. Nouailletas, S. Nowak, H. Nyström, R. Ochoukov, N. Offeddu, S. Olasz, C. Olde, F. Oliva, D. Oliveira, H.J.C. Oliver, P. Ollus, J. Ongena, F.P. Orsitto, N. Osborne, R. Otin, P. Oyola Dominguez, D.I. Palade, S. Palomba, O. Pan, N. Panadero, E. Panontin, A. Papadopoulos, P. Papagiannis, G. Papp, V.V. Parail, C. Pardanaud, J. Parisi, A. Parrott, K. Paschalidis, M. Passoni, F. Pastore, A. Patel, B. Patel, A. Pau, G. Pautasso, R. Pavlichenko, E. Pawelec, B. Pegourie, G. Pelka, E. Peluso, A. Perek, E. Perelli Cippo, C. Perez Von Thun, P. Petersson, G. Petravich, Y. Peysson, V. Piergotti, L. Pigatto, C. Piron, L. Piron, A. Pironti, F. Pisano, U. Plank, B. Ploeckl, V. Plyusnin, A. Podolnik, Y. Poels, G. Pokol, J. Poley, G. Por, M. Poradzinski, F. Porcelli, L. Porte, C. Possieri, A. Poulsen, I. Predebon, G. Pucella, M. Pueschel, P. Puglia, O. Putignano, T. Pütterich, V. Quadri, A. Quercia, M. Rabinski, L. Radovanovic, R. Ragona, H. Raj, M. Rasinski, J. Rasmussen, G. Ratta, S. Ratynskaia, R. Rayaprolu, M. Rebai, A. Redl, D. Rees, D. Refy, M. Reich, H. Reimerdes, B.C.G. Reman, O. Renders, C. Reux, D. Ricci, M. Richou, S. Rienacker, D. Rigamonti, F. Rigollet, F.G. Rimini, D. Ripamonti, N. Rispoli, N. Rivals, J.F. Rivero Rodriguez, C. Roach, G. Rocchi, S. Rode, P. Rodrigues, J. Romazanov, C.F. Romero Madrid, J. Rosato, R. Rossi, G. Rubino, J. Rueda Rueda, J. Ruiz Ruiz, P. Ryan, D. Ryan, S. Saarelma, R. Sabot, M. Salewski, A. Salmi, L. Sanchis, A. Sand, J. Santos, K. Särkimäki, M. Sassano, O. Sauter, G. Schettini, S. Schmuck, P. Schneider, N. Schoonheere, R. Schramm, R. Schrittwieser, C. Schuster, N. Schwarz, F. Sciortino, M. Scotto D’Abusco, S. Scully, A. Selce, L. Senni, M. Senstius, G. Sergienko, S.E. Sharapov, R. Sharma, A. Shaw, U. Sheikh, G. Sias, B. Sieglin, S.A. Silburn, C. Silva, A. Silva, D. Silvagni, B. Simmendefeldt Schmidt, L. Simons, J. Simpson, L. Singh, S. Sipilä, Y. Siusko, S. Smith, A. Snicker, E.R. Solano, V. Solokha, M. Sos, C. Sozzi, F. Spineanu, G. Spizzo, M. Spolaore, L. Spolladore, C. Srinivasan, A. Stagni, Z. Stancar, G. Stankunas, J. Stober, P. Strand, C.I. Stuart, F. Subba, G.Y. Sun, H.J. Sun, W. Suttrop, J. Svoboda, T. Szepesi, G. Szepesi, B. Tal, T. Tala, P. Tamain, G. Tardini, M. Tardocchi, D. Taylor, G. Telesca, A. Tenaglia, A. Terra, D. Terranova, D. Testa, C. Theiler, E. Tholerus, B. Thomas, E. Thoren, A. Thornton, A. Thrysoe, Q. TICHIT, W. Tierens, A. Titarenko, P. Tolias, E. Tomasina, M. Tomes, E. Tonello, A. Tookey, M. Toscano Jiménez, C. Tsironis, C. Tsui, A. Tykhyy, M. Ugoletti, M. Usoltseva, D.F. Valcarcel, A. Valentini, M. Valisa, M. Vallar, M. Valovic, SI. Valvis, M. van Berkel, D. Van Eester, S. Van Mulders, M. van Rossem, R. Vann, B. Vanovac, J. Varela Rodriguez, J. Varje, S. Vartanian, M. Vecsei, L. Velarde Gallardo, M. Veranda, T. Verdier, G. Verdoolaege, K. Verhaegh, L. Vermare, G. Verona Rinati, J. Vicente, E. Viezzer, L. Vignitchouk, F. Villone, B. Vincent, P. Vincenzi, M.O. Vlad, G. Vogel, I. Voitsekhovitch, I. Voldiner, P. Vondracek, N.M.T. VU, T. Vuoriheimo, C. Wade, E. Wang, T. Wauters, M. Weiland, H. Weisen, N. Wendler, D. Weston, A. Widdowson, S. Wiesen, M. Wiesenberger, T. Wijkamp, M. Willensdorfer, T. Wilson, A. Wojenski, C. Wuethrich, I. Wyss, L. Xiang, S. Xu, D. Yadykin, Y. Yakovenko, H. Yang, V. Yanovskiy, R. Yi, B. Zaar, G. Zadvitskiy, L. Zakharov, P. Zanca, D. Zarzoso, Y. Zayachuk, J. Zebrowski, M. Zerbini, P. Zestanakis, C. F. B. Zimmermann, M. Zlobinski, A. Zohar, V.K. Zotta, X. Zou, M. Zuin, M. Zurita, and I. Zychor

Subjects
JET, ASDEX Upgrade, MAST-U, TCV, WEST, Tokamak Exploitation Task Force, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Within the 9th European Framework programme, since 2021 EUROfusion is operating five tokamaks under the auspices of a single Task Force called ‘Tokamak Exploitation’. The goal is to benefit from the complementary capabilities of each machine in a coordinated way and help in developing a scientific output scalable to future largre machines. The programme of this Task Force ensures that ASDEX Upgrade, MAST-U, TCV, WEST and JET (since 2022) work together to achieve the objectives of Missions 1 and 2 of the EUROfusion Roadmap: i) demonstrate plasma scenarios that increase the success margin of ITER and satisfy the requirements of DEMO and, ii) demonstrate an integrated approach that can handle the large power leaving ITER and DEMO plasmas. The Tokamak Exploitation task force has therefore organized experiments on these two missions with the goal to strengthen the physics and operational basis for the ITER baseline scenario and for exploiting the recent plasma exhaust enhancements in all four devices (PEX: Plasma EXhaust) for exploring the solution for handling heat and particle exhaust in ITER and develop the conceptual solutions for DEMO. The ITER Baseline scenario has been developed in a similar way in ASDEX Upgrade, TCV and JET. Key risks for ITER such as disruptions and run-aways have been also investigated in TCV, ASDEX Upgrade and JET. Experiments have explored successfully different divertor configurations (standard, super-X, snowflakes) in MAST-U and TCV and studied tungsten melting in WEST and ASDEX Upgrade. The input from the smaller devices to JET has also been proven successful to set-up novel control schemes on disruption avoidance and detachment.

Published
2024
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7. First experimental results of the PAM LHCD launcher at 2.45 GHz on EAST

Author

M.H. Li, L. Liu, M. Wang, Y. Yang, C.B. Wu, Y.C. Li, G.H. Yan, B.J. Ding, L.M. Zhao, Z.G. Wu, H. Jia, W.Y. Zhou, M. Goniche, J. Hillairet, Y. Peysson, A. Ekedahl, Q. Zang, L. Zhang, X.J. Zhang, Y.W. Sun, J.P. Qian, and X.Z. Gong

Subjects
PAM launcher, LHCD, wave coupling, power spectrum, current drive efficiency, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

This paper presents the first results of a passive active multijunction (PAM) launcher at 2.45 GHz during the lower hybrid current drive (LHCD) experiments on EAST. Good coupling performance with a power reflection coefficient ( RC ) ∼3% has been achieved at the plasma–antenna distance up to ∼11 cm in L-mode edge plasmas without local gas puffing near the PAM launcher. Reliable power coupling of this PAM during the edge perturbations induced by type I edge localized modes (ELMs) has been successfully demonstrated. Compared with the old full active multijunction (FAM) launcher, the new PAM can be placed ∼2 cm further away from the plasma in normal operations, which is in good agreement with the previous prediction (Li et al 2019 Fusion Eng. Des. 147 111 250), by the linear wave–plasma coupling code ALOHA (Hillairet et al 2010 Nucl. Fusion 50 125 010). The flexibility of the power spectrum by changing the phase difference between adjacent modules was validated and ray-tracing/Fokker–Planck simulations can reproduce the experimental features. The achievable power handling is as high as 25 MW m ^−2 , although with a shot pulse length of ∼10 s. The first experiment successfully demonstrated the coupling performance of a PAM launcher at low density and this launcher construction provides helpful engineering experience for the 4.6 GHz PAM development in the near future on EAST.

Published
2023
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8. Long plasma duration operation analyses with an international multi-machine (tokamaks and stellarators) database

Author

X. Litaudon, H.-S. Bosch, T. Morisaki, M. Barbarino, A. Bock, E. Belonohy, S. Brezinsek, J. Bucalossi, S. Coda, R. Daniel, A. Ekedahl, K. Hanada, C. Holcomb, J. Huang, S. Ide, M. Jakubowski, B. V. Kuteev, E. Lerche, T. Luce, P. Maget, Y. Song, J. Stober, D. VAN Houtte, Y. Xi, L. Xue, S. Yoon, B. Zhang, and JET contributors

Subjects
nuclear fusion, long plasma duration operation, international multi-machine (tokamaks and stellarators) database, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Combined high-fusion performance and long-pulse operation is one of the key integration challenges for fusion energy development in magnetic devices. Addressing these challenges requires an integrated vision of physics and engineering aspects with the purpose of simultaneously increasing time duration and fusion performance. Significant progress has been made in tokamaks and stellarators, including very recent achievement in duration and/or performance. This progress is reviewed by analyzing the experimental data (109 plasma pulses with a total of 3200 data points, i.e. on average 29 data per pulse) provided by ten tokamaks (in alphabetical order: Axially Symmetric Divertor Experiment Upgrade, DIII-D, Experimental Advanced Superconducting Tokamak, Joint European Torus, JT-60 Upgrade, Korea Superconducting Tokamak Advanced Research, tokamak à configuration variable, Tokamak Fusion Test Reactor, Tore Supra, W Environment in Steady-State Tokamak) and two stellarators (Large Helical Device and Wendelstein 7-X) expanding the pioneering work of Kikuchi (Kikuchi M. and Azumi M. 2015 Frontiers in Fusion Research II: Introduction to Modern Tokamak Physics (Springer)). Data have been gathered up to January 2022 and coordination has been provided by the recently created International Energy Agency-International Atomic Energy Agency international C oordination on I nternational C hallenges on L ong duration OP eration group. By exploiting the multi-machine international database, recent progress in terms of injected energies (e.g. 1730 MJ in L-mode, 425 MJ in H-mode), durations (1056 s in L-mode, 101 s in H-mode), injected powers, and sustained performance will be reviewed. Progress has been made to sustain long-pulse operation in tokamaks and stellarators with superconducting coils, actively cooled components, and/or with metallic walls. The graph of the fusion triple products as a function of duration shows a dramatic reduction of, at least two orders of magnitude when increasing the plasma duration from less than 1 s to 100 s. Indeed, long-pulse operation is usually reached in dominant electron-heating modes at reduced density (current drive optimization) but with low ion temperatures ranging from 1 to 3 keV for discharges above 100 s. Difficulties in extending the duration may arise from coupling high heating powers over long durations and the evolving plasma-wall interaction towards an unstable operational domain. Possible causes limiting the duration and critical issues to be addressed prior to ITER operation and DEMO design are reported and analyzed.

Published
2023
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9. Effect of edge plasma density on hot spot in LHCD plasma in EAST

Author

B.J. Ding, C.B. Wu, Y.C. Li, M.H. Li, Y.F. Wang, B. Zhang, G.H. Yan, H.Q. Liu, L. Wang, M. Wang, R. Ding, H.C. Hu, H. Lian, R. Cesario, A.A. Tuccillo, S.G. Baek, P Bonoli, A. Ekedahl, J.F. Shan, F.K. Liu, J.P. Qian, X.Z. Gong, and B.N. Wan

Subjects
Lower hybrid current drive, Hot spot, Edge plasma density, Heat flux, Tokamak, Nuclear engineering. Atomic power, TK9001-9401
Abstract

Hot spot is a serious challenge limiting long pulse operation with LHCD (lower hybrid current drive) in tokamak. In order to mitigate the hot spot in guard limiter and improve LHCD capability, effect of edge plasma density on inducing hot spot and current drive has been studied in EAST. The temperature in the guard limiter of the LH antenna, inducing hot spot directly, increases with edge density and LH power. Studies show that the hot spot is mainly ascribed to the heat flux in front of LH antenna. Further simulation indicates that such spot corresponds to the peak position of edge density due to local LH electric field. In addition, due to the stronger parametric instability (PI) behavior in the case of higher edge density, the current drive capability decreases with edge density. Strike-point splitting behaviors appear with density increase, in agreement with current profiles in the edge region and the reduction of total driven current, suggesting that more power is deposited in edge region, which does more contribution to hot spot. Above studies offer one possible idea to optimize the edge density so as to satisfy the coupling, mitigate the heat flux in the guard limiter, and improve current drive capability for fusion device.

Published
2021
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10. Metallic impurity sources behavior during ICRH in EAST

Author

G. Urbanczyk, X.J. Zhang, L. Colas, A. Ekedahl, S. Heuraux, J.G. Li, C.M. Qin, Y.P. Zhao, L. Zhang, and X.D. Yang

Subjects
Nuclear engineering. Atomic power, TK9001-9401
Abstract

High-Z impurities production is often observed during Ion Cyclotron Range of Frequencies (ICRF) waves’ injection, which are likely due to RF sheath formation on solid materials. Based on Extreme UV (EUV) spectrometry data, this study in EAST consists in extracting information on plasma-surface interactions during ICRH. Intensities of the different spectral lines normalized to line-integrated plasma density, exhibit different parametric dependencies over scans of ICRH and LH power and for different toroidal phasing between straps. Materials close and magnetically-connected to an active antenna tend to show better correlation with ICRF parameters – such as power and feeding scheme – than those which are far away or not connected. ICRF phasing did not have influence on impurity, probably due to the absence of feedback control. It is further shown that the plasma content in impurities from divertor region better correlates with the total injected power rather than with ICRF power. Keywords: ICRH, Impurity source, EUV spectrometer

Published
2018
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11. Measurements of the fast electron bremsstrahlung during lower hybrid current drive in the HL-2A tokamak

Author

Y. P. Zhang, D. Mazon, Y. Peysson, P. Malard, P. F. Zhang, J. Zhang, X. L. Zou, J. Zhou, H. B. Xu, X. Y. Bai, J. W. Yang, G. L. Yuan, X. Y. Song, X. Li, W. L. Zhong, X. T. Ding, W. Chen, Y. G. Li, T. Hoang, L. Delpech, A. Ekedahl, M. Isobe, X. M. Song, B. Lu, Yi Liu, Z. B. Shi, Q. W. Yang, M. Xu, X. R. Duan, and Y. Liu

Subjects
Physics, QC1-999
Abstract

Physics related to fast electrons in lower hybrid (LH) current drive (LHCD) plasma is a very important issue, since these particles will play an important role in runaway electron (RE) generation and lower hybrid wave (LHW)-related physics. Utilizing a new hard X-ray (HXR) pinhole camera, recent HL-2A tokamak experiments have devoted to enhancing the understanding of the physics on fast electrons and LHW. The fast electron bremsstrahlung (FEB) emission in the HXR energy range between 20 and 200 keV was measured by the HXR camera. To study the conversion of LHW-produced fast electrons into REs, a very short pulse of LHW, so-called “blip”, with duration of 5 ms was injected into the plasma during the current flattop phase. A strong enhancement of REs was induced by the blip injection. Measurements from the HXR camera show that the fast electrons generated by LHWs is mainly concentrated in 40-60 keV, which is well consistent with the calculated value based on Landau damping theory. The energy of these seed electrons is higher than the critical runaway energy. This phenomenon may be come from the synergetic effects of Dreicer and avalanche RE generation. Moreover, the measurements indicate that the spatial distribution of the fast electrons during LHCD has a peaked profile, implying that the fast electrons are mainly produced in the plasma core. It also suggests that the energy of the LHW mainly deposited in the plasma core region.

Published
2019
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12. Global scaling of the heat transport in fusion plasmas

Author

Sara Moradi, Johan Anderson, Michele Romanelli, Hyun-Tae Kim, JET contributors, X. Litaudon, S. Abduallev, M. Abhangi, P. Abreu, M. Afzal, K. M. Aggarwal, T. Ahlgren, J. H. Ahn, L. Aho-Mantila, N. Aiba, M. Airila, R. Albanese, V. Aldred, D. Alegre, E. Alessi, P. Aleynikov, A. Alfier, A. Alkseev, M. Allinson, B. Alper, E. Alves, G. Ambrosino, R. Ambrosino, L. Amicucci, V. Amosov, E. Andersson Sundén, M. Angelone, M. Anghel, C. Angioni, L. Appel, C. Appelbee, P. Arena, M. Ariola, H. Arnichand, S. Arshad, A. Ash, N. Ashikawa, V. Aslanyan, O. Asunta, F. Auriemma, Y. Austin, L. Avotina, M. D. Axton, C. Ayres, M. Bacharis, A. Baciero, D. Baião, S. Bailey, A. Baker, I. Balboa, M. Balden, N. Balshaw, R. Bament, J. W. Banks, Y. F. Baranov, M. A. Barnard, D. Barnes, M. Barnes, R. Barnsley, A. Baron Wiechec, L. Barrera Orte, M. Baruzzo, V. Basiuk, M. Bassan, R. Bastow, A. Batista, P. Batistoni, R. Baughan, B. Bauvir, L. Baylor, B. Bazylev, J. Beal, P. S. Beaumont, M. Beckers, B. Beckett, A. Becoulet, N. Bekris, M. Beldishevski, K. Bell, F. Belli, M. Bellinger, É. Belonohy, N. Ben Ayed, N. A. Benterman, H. Bergsȧker, J. Bernardo, M. Bernert, M. Berry, L. Bertalot, C. Besliu, M. Beurskens, B. Bieg, J. Bielecki, T. Biewer, M. Bigi, P. Bìlkovà, F. Binda, A. Bisoffi, J. P. S. Bizarro, C. Björkas, J. Blackburn, K. Blackman, T. R. Blackman, P. Blanchard, P. Blatchford, V. Bobkov, A. Boboc, G. Bodnàr, O. Bogar, I. Bolshakova, T. Bolzonella, N. Bonanomi, F. Bonelli, J. Boom, J. Booth, D. Borba, D. Borodin, I. Borodkina, A. Botrugno, C. Bottereau, P. Boulting, C. Bourdelle, M. Bowden, C. Bower, C. Bowman, T. Boyce, C. Boyd, H. J. Boyer, J. M. A. Bradshaw, V. Braic, R. Bravanec, B. Breizman, S. Bremond, P. D. Brennan, S. Breton, A. Brett, S. Brezinsek, M. D. J. Bright, M. Brix, W. Broeckx, M. Brombin, A. Brosawski, D. P. D. Brown, M. Brown, E. Bruno, J. Bucalossi, J. Buch, J. Buchanan, M. A. Buckley, R. Budny, H. Bufferand, M. Bulman, N. Bulmer, P. Bunting, P. Buratti, A. Burckhart, A. Buscarino, A. Busse, N. K. Butler, I. Bykov, J. Byrne, P. Cahyna, G. Calabrò, I. Calvo, Y. Camenen, P. Camp, D. C. Campling, J. Cane, B. Cannas, A. J. Capel, P. J. Card, A. Cardinali, P. Carman, M. Carr, D. Carralero, L. Carraro, B. B. Carvalho, I. Carvalho, P. Carvalho, F. J. Casson, C. Castaldo, N. Catarino, J. Caumont, F. Causa, R. Cavazzana, K. Cave-Ayland, M. Cavinato, M. Cecconello, S. Ceccuzzi, E. Cecil, A. Cenedese, R. Cesario, C. D. Challis, M. Chandler, D. Chandra, C. S. Chang, A. Chankin, I. T. Chapman, S. C. Chapman, M. Chernyshova, G. Chitarin, G. Ciraolo, D. Ciric, J. Citrin, F. Clairet, E. Clark, M. Clark, R. Clarkson, D. Clatworthy, C. Clements, M. Cleverly, J. P. Coad, P. A. Coates, A. Cobalt, V. Coccorese, V. Cocilovo, S. Coda, R. Coelho, J. W. Coenen, I. Coffey, L. Colas, S. Collins, D. Conka, S. Conroy, N. Conway, D. Coombs, D. Cooper, S. R. Cooper, C. Corradino, Y. Corre, G. Corrigan, S. Cortes, D. Coster, A. S. Couchman, M. P. Cox, T. Craciunescu, S. Cramp, R. Craven, F. Crisanti, G. Croci, D. Croft, K. Crombé, R. Crowe, N. Cruz, G. Cseh, A. Cufar, A. Cullen, M. Curuia, A. Czarnecka, H. Dabirikhah, P. Dalgliesh, S. Dalley, J. Dankowski, D. Darrow, O. Davies, W. Davis, C. Day, I. E. Day, M. De Bock, A. de Castro, E. de la Cal, E. de la Luna, G. De Masi, J. L. de Pablos, G. De Temmerman, G. De Tommasi, P. de Vries, K. Deakin, J. Deane, F. Degli Agostini, R. Dejarnac, E. Delabie, N. den Harder, R. O. Dendy, J. Denis, P. Denner, S. Devaux, P. Devynck, F. Di Maio, A. Di Siena, C. Di Troia, P. Dinca, R. Dinca, B. Ding, T. Dittmar, H. Doerk, R. P. Doerner, T. Donné, S. E. Dorling, S. Dormido-Canto, S. Doswon, D. Douai, P. T. Doyle, A. Drenik, P. Drewelow, P. Drews, Ph. Duckworth, R. Dumont, P. Dumortier, D. Dunai, M. Dunne, I. Duran, F. Durodié, P. Dutta, B. P. Duval, R. Dux, K. Dylst, N. Dzysiuk, P. V. Edappala, J. Edmond, A. M. Edwards, J. Edwards, Th. Eich, A. Ekedahl, R. El-Jorf, C. G. Elsmore, M. Enachescu, G. Ericsson, F. Eriksson, J. Eriksson, L. G. Eriksson, B. Esposito, S. Esquembri, H. G. Esser, D. Esteve, B. Evans, G. E. Evans, G. Evison, G. D. Ewart, D. Fagan, M. Faitsch, D. Falie, A. Fanni, A. Fasoli, J. M. Faustin, N. Fawlk, L. Fazendeiro, N. Fedorczak, R. C. Felton, K. Fenton, A. Fernades, H. Fernandes, J. Ferreira, J. A. Fessey, O. Février, O. Ficker, A. Field, S. Fietz, A. Figueiredo, J. Figueiredo, A. Fil, P. Finburg, M. Firdaouss, U. Fischer, L. Fittill, M. Fitzgerald, D. Flammini, J. Flanagan, C. Fleming, K. Flinders, N. Fonnesu, J. M. Fontdecaba, A. Formisano, L. Forsythe, L. Fortuna, E. Fortuna-Zalesna, M. Fortune, S. Foster, T. Franke, T. Franklin, M. Frasca, L. Frassinetti, M. Freisinger, R. Fresa, D. Frigione, V. Fuchs, D. Fuller, S. Futatani, J. Fyvie, K. Gàl, D. Galassi, K. Galazka, J. Galdon-Quiroga, J. Gallagher, D. Gallart, R. Galvão, X. Gao, Y. Gao, J. Garcia, A. Garcia-Carrasco, M. Garca-Munoz, J.-L. Gardarein, L. Garzotti, P. Gaudio, E. Gauthier, D. F. Gear, S. J. Gee, B. Geiger, M. Gelfusa, S. Gerasimov, G. Gervasini, M. Gethins, Z. Ghani, M. Ghate, M. Gherendi, J. C. Giacalone, L. Giacomelli, C. S. Gibson, T. Giegerich, C. Gil, L. Gil, S. Gilligan, D. Gin, E. Giovannozzi, J. B. Girardo, C. Giroud, G. Giruzzi, S. Glöggler, J. Godwin, J. Goff, P. Gohil, V. Goloborod'ko, R. Gomes, B. Goncalves, M. Goniche, M. Goodliffe, A. Goodyear, G. Gorini, M. Gosk, R. Goulding, A. Goussarov, R. Gowland, B. Graham, M. E. Graham, J. P. Graves, N. Grazier, P. Grazier, N. R. Green, H. Greuner, B. Grierson, F. S. Griph, C. Grisolia, D. Grist, M. Groth, R. Grove, C. N. Grundy, J. Grzonka, D. Guard, C. Guérard, C. Guillemaut, R. Guirlet, C. Gurl, H. H. Utoh, L. J. Hackett, S. Hacquin, A. Hagar, R. Hager, A. Hakola, M. Halitovs, S. J. Hall, S. P. Hallworth Cook, C. Hamlyn-Harris, K. Hammond, C. Harrington, J. Harrison, D. Harting, F. Hasenbeck, Y. Hatano, D. R. Hatch, T. D. V. Haupt, J. Hawes, N. C. Hawkes, J. Hawkins, P. Hawkins, P. W. Haydon, N. Hayter, S. Hazel, P. J. L. Heesterman, K. Heinola, C. Hellesen, T. Hellsten, W. Helou, O. N. Hemming, T. C. Hender, M. Henderson, S. S. Henderson, R. Henriques, D. Hepple, G. Hermon, P. Hertout, C. Hidalgo, E. G. Highcock, M. Hill, J. Hillairet, J. Hillesheim, D. Hillis, K. Hizanidis, A. Hjalmarsson, J. Hobirk, E. Hodille, C. H. A. Hogben, G. M. D. Hogeweij, A. Hollingsworth, S. Hollis, D. A. Homfray, J. Horàcek, G. Hornung, A. R. Horton, L. D. Horton, L. Horvath, S. P. Hotchin, M. R. Hough, P. J. Howarth, A. Hubbard, A. Huber, V. Huber, T. M. Huddleston, M. Hughes, G. T. A. Huijsmans, C. L. Hunter, P. Huynh, A. M. Hynes, D. Iglesias, N. Imazawa, F. Imbeaux, M. Imrìŝek, M. Incelli, P. Innocente, M. Irishkin, I. Ivanova-Stanik, S. Jachmich, A. S. Jacobsen, P. Jacquet, J. Jansons, A. Jardin, A. Järvinen, F. Jaulmes, S. Jednoróq, I. Jenkins, C. Jeong, I. Jepu, E. Joffrin, R. Johnson, T. Johnson, Jane Johnston, L. Joita, G. Jones, T. T. C. Jones, K. K. Hoshino, A. Kallenbach, K. Kamiya, J. Kaniewski, A. Kantor, A. Kappatou, J. Karhunen, D. Karkinsky, I. Karnowska, M. Kaufman, G. Kaveney, Y. Kazakov, V. Kazantzidis, D. L. Keeling, T. Keenan, J. Keep, M. Kempenaars, C. Kennedy, D. Kenny, J. Kent, O. N. Kent, E. Khilkevich, H. T. Kim, H. S. Kim, A. Kinch, C. King, D. King, R. F. King, D. J. Kinna, V. Kiptily, A. Kirk, K. Kirov, A. Kirschner, G. Kizane, C. Klepper, A. Klix, P. Knight, S. J. Knipe, S. Knott, T. Kobuchi, F. Köchl, G. Kocsis, I. Kodeli, L. Kogan, D. Kogut, S. Koivuranta, Y. Kominis, M. Köppen, B. Kos, T. Koskela, H. R. Koslowski, M. Koubiti, M. Kovari, E. Kowalska-Strzeciwilk, A. Krasilnikov, V. Krasilnikov, N. Krawczyk, M. Kresina, K. Krieger, A. Krivska, U. Kruezi, I. Ksiazek, A. Kukushkin, A. Kundu, T. Kurki-Suonio, S. Kwak, R. Kwiatkowski, O. J. Kwon, L. Laguardia, A. Lahtinen, A. Laing, N. Lam, H. T. Lambertz, C. Lane, P. T. Lang, S. Lanthaler, J. Lapins, A. Lasa, J. R. Last, E. Laszynska, R. Lawless, A. Lawson, K. D. Lawson, A. Lazaros, E. Lazzaro, J. Leddy, S. Lee, X. Lefebvre, H. J. Leggate, J. Lehmann, M. Lehnen, D. Leichtle, P. Leichuer, F. Leipold, I. Lengar, M. Lennholm, E. Lerche, A. Lescinskis, S. Lesnoj, E. Letellier, M. Leyland, W. Leysen, L. Li, Y. Liang, J. Likonen, J. Linke, Ch. Linsmeier, B. Lipschultz, G. Liu, Y. Liu, V. P. Lo Schiavo, T. Loarer, A. Loarte, R. C. Lobel, B. Lomanowski, P. J. Lomas, J. Lönnroth, J. M. López, J. López-Razola, R. Lorenzini, U. Losada, J. J. Lovell, A. B. Loving, C. Lowry, T. Luce, R. M. A. Lucock, A. Lukin, C. Luna, M. Lungaroni, C. P. Lungu, M. Lungu, A. Lunniss, I. Lupelli, A. Lyssoivan, N. Macdonald, P. Macheta, K. Maczewa, B. Magesh, P. Maget, C. Maggi, H. Maier, J. Mailloux, T. Makkonen, R. Makwana, A. Malaquias, A. Malizia, P. Manas, A. Manning, M. E. Manso, P. Mantica, M. Mantsinen, A. Manzanares, Ph. Maquet, Y. Marandet, N. Marcenko, C. Marchetto, O. Marchuk, M. Marinelli, M. Marinucci, T. Markovic, D. Marocco, L. Marot, C. A. Marren, R. Marshal, A. Martin, Y. Martin, A. Martín de Aguilera, F. J. Martínez, J. R. Martín-Solís, Y. Martynova, S. Maruyama, A. Masiello, M. Maslov, S. Matejcik, M. Mattei, G. F. Matthews, F. Maviglia, M. Mayer, M. L. Mayoral, T. May-Smith, D. Mazon, C. Mazzotta, R. McAdams, P. J. McCarthy, K. G. McClements, O. McCormack, P. A. McCullen, D. McDonald, S. McIntosh, R. McKean, J. McKehon, R. C. Meadows, A. Meakins, F. Medina, M. Medland, S. Medley, S. Meigh, A. G. Meigs, G. Meisl, S. Meitner, L. Meneses, S. Menmuir, K. Mergia, I. R. Merrigan, Ph. Mertens, S. Meshchaninov, A. Messiaen, H. Meyer, S. Mianowski, R. Michling, D. Middleton-Gear, J. Miettunen, F. Militello, E. Militello-Asp, G. Miloshevsky, F. Mink, S. Minucci, Y. Miyoshi, J. Mlynàr, D. Molina, I. Monakhov, M. Moneti, R. Mooney, S. Moradi, S. Mordijck, L. Moreira, R. Moreno, F. Moro, A. W. Morris, J. Morris, L. Moser, S. Mosher, D. Moulton, A. Murari, A. Muraro, S. Murphy, N. N. Asakura, Y. S. Na, F. Nabais, R. Naish, T. Nakano, E. Nardon, V. Naulin, M. F. F. Nave, I. Nedzelski, G. Nemtsev, F. Nespoli, A. Neto, R. Neu, V. S. Neverov, M. Newman, K. J. Nicholls, T. Nicolas, A. H. Nielsen, P. Nielsen, E. Nilsson, D. Nishijima, C. Noble, M. Nocente, D. Nodwell, K. Nordlund, H. Nordman, R. Nouailletas, I. Nunes, M. Oberkofler, T. Odupitan, M. T. Ogawa, T. O'Gorman, M. Okabayashi, R. Olney, O. Omolayo, M. O'Mullane, J. Ongena, F. Orsitto, J. Orszagh, B. I. Oswuigwe, R. Otin, A. Owen, R. Paccagnella, N. Pace, D. Pacella, L. W. Packer, A. Page, E. Pajuste, S. Palazzo, S. Pamela, S. Panja, P. Papp, R. Paprok, V. Parail, M. Park, F. Parra Diaz, M. Parsons, R. Pasqualotto, A. Patel, S. Pathak, D. Paton, H. Patten, A. Pau, E. Pawelec, C. Paz Soldan, A. Peackoc, I. J. Pearson, S.-P. Pehkonen, E. Peluso, C. Penot, A. Pereira, R. Pereira, P. P. Pereira Puglia, C. Perez von Thun, S. Peruzzo, S. Peschanyi, M. Peterka, P. Petersson, G. Petravich, A. Petre, N. Petrella, V. Petrzilka, Y. Peysson, D. Pfefferlé, V. Philipps, M. Pillon, G. Pintsuk, P. Piovesan, A. Pires dos Reis, L. Piron, A. Pironti, F. Pisano, R. Pitts, F. Pizzo, V. Plyusnin, N. Pomaro, O. G. Pompilian, P. J. Pool, S. Popovichev, M. T. Porfiri, C. Porosnicu, M. Porton, G. Possnert, S. Potzel, T. Powell, J. Pozzi, V. Prajapati, R. Prakash, G. Prestopino, D. Price, M. Price, R. Price, P. Prior, R. Proudfoot, G. Pucella, P. Puglia, M. E. Puiatti, D. Pulley, K. Purahoo, Th. Pütterich, E. Rachlew, M. Rack, R. Ragona, M. S. J. Rainford, A. Rakha, G. Ramogida, S. Ranjan, C. J. Rapson, J. J. Rasmussen, K. Rathod, G. Rattà, S. Ratynskaia, G. Ravera, C. Rayner, M. Rebai, D. Reece, A. Reed, D. Réfy, B. Regan, J. Regana, M. Reich, N. Reid, F. Reimold, M. Reinhart, M. Reinke, D. Reiser, D. Rendell, C. Reux, S. D. A. Reyes Cortes, S. Reynolds, V. Riccardo, N. Richardson, K. Riddle, D. Rigamonti, F. G. Rimini, J. Risner, M. Riva, C. Roach, R. J. Robins, S. A. Robinson, T. Robinson, D. W. Robson, R. Roccella, R. Rodionov, P. Rodrigues, J. Rodriguez, V. Rohde, F. Romanelli, M. Romanelli, S. Romanelli, J. Romazanov, S. Rowe, M. Rubel, G. Rubinacci, G. Rubino, L. Ruchko, M. Ruiz, C. Ruset, J. Rzadkiewicz, S. Saarelma, R. Sabot, E. Safi, P. Sagar, G. Saibene, F. Saint-Laurent, M. Salewski, A. Salmi, R. Salmon, F. Salzedas, D. Samaddar, U. Samm, D. Sandiford, P. Santa, M. I. K. Santala, B. Santos, A. Santucci, F. Sartori, R. Sartori, O. Sauter, R. Scannell, T. Schlummer, K. Schmid, V. Schmidt, S. Schmuck, M. Schneider, K. Schöpf, D. Schwörer, S. D. Scott, G. Sergienko, M. Sertoli, A. Shabbir, S. E. Sharapov, A. Shaw, R. Shaw, H. Sheikh, A. Shepherd, A. Shevelev, A. Shumack, G. Sias, M. Sibbald, B. Sieglin, S. Silburn, A. Silva, C. Silva, P. A. Simmons, J. Simpson, J. Simpson-Hutchinson, A. Sinha, S. K. Sipilä, A. C. C. Sips, P. Sirén, A. Sirinelli, H. Sjöstrand, M. Skiba, R. Skilton, K. Slabkowska, B. Slade, N. Smith, P. G. Smith, R. Smith, T. J. Smith, M. Smithies, L. Snoj, S. Soare, E. R. Solano, A. Somers, C. Sommariva, P. Sonato, A. Sopplesa, J. Sousa, C. Sozzi, S. Spagnolo, T. Spelzini, F. Spineanu, G. Stables, I. Stamatelatos, M. F. Stamp, P. Staniec, G. Stankunas, C. Stan-Sion, M. J. Stead, E. Stefanikova, I. Stepanov, A. V. Stephen, M. Stephen, A. Stevens, B. D. Stevens, J. Strachan, P. Strand, H. R. Strauss, P. Ström, G. Stubbs, W. Studholme, F. Subba, H. P. Summers, J. Svensson, L. Swiderski, T. Szabolics, M. Szawlowski, G. Szepesi, T. T. Suzuki, B. Tàl, T. Tala, A. R. Talbot, S. Talebzadeh, C. Taliercio, P. Tamain, C. Tame, W. Tang, M. Tardocchi, L. Taroni, D. Taylor, K. A. Taylor, D. Tegnered, G. Telesca, N. Teplova, D. Terranova, D. Testa, E. Tholerus, J. Thomas, J. D. Thomas, P. Thomas, A. Thompson, C.-A. Thompson, V. K. Thompson, L. Thorne, A. Thornton, A. S. Thrysoe, P. A. Tigwell, N. Tipton, I. Tiseanu, H. Tojo, M. Tokitani, P. Tolias, M. Tomes, P. Tonner, M. Towndrow, P. Trimble, M. Tripsky, M. Tsalas, P. Tsavalas, D. Tskhakaya jun, I. Turner, M. M. Turner, M. Turnyanskiy, G. Tvalashvili, S. G. J. Tyrrell, A. Uccello, Z. Ul-Abidin, J. Uljanovs, D. Ulyatt, H. Urano, I. Uytdenhouwen, A. P. Vadgama, D. Valcarcel, M. Valentinuzzi, M. Valisa, P. Vallejos Olivares, M. Valovic, M. Van De Mortel, D. Van Eester, W. Van Renterghem, G. J. van Rooij, J. Varje, S. Varoutis, S. Vartanian, K. Vasava, T. Vasilopoulou, J. Vega, G. Verdoolaege, R. Verhoeven, C. Verona, G. Verona Rinati, E. Veshchev, N. Vianello, J. Vicente, E. Viezzer, S. Villari, F. Villone, P. Vincenzi, I. Vinyar, B. Viola, A. Vitins, Z. Vizvary, M. Vlad, I. Voitsekhovitch, P. Vondràcek, N. Vora, T. Vu, W. W. Pires de Sa, B. Wakeling, C. W. F. Waldon, N. Walkden, M. Walker, R. Walker, M. Walsh, E. Wang, N. Wang, S. Warder, R. J. Warren, J. Waterhouse, N. W. Watkins, C. Watts, T. Wauters, A. Weckmann, J. Weiland, H. Weisen, M. Weiszflog, C. Wellstood, A. T. West, M. R. Wheatley, S. Whetham, A. M. Whitehead, B. D. Whitehead, A. M. Widdowson, S. Wiesen, J. Wilkinson, J. Williams, M. Williams, A. R. Wilson, D. J. Wilson, H. R. Wilson, J. Wilson, M. Wischmeier, G. Withenshaw, A. Withycombe, D. M. Witts, D. Wood, R. Wood, C. Woodley, S. Wray, J. Wright, J. C. Wright, J. Wu, S. Wukitch, A. Wynn, T. Xu, D. Yadikin, W. Yanling, L. Yao, V. Yavorskij, M. G. Yoo, C. Young, D. Young, I. D. Young, R. Young, J. Zacks, R. Zagorski, F. S. Zaitsev, R. Zanino, A. Zarins, K. D. Zastrow, M. Zerbini, W. Zhang, Y. Zhou, E. Zilli, V. Zoita, S. Zoletnik, and I. Zychor

Subjects
Physics, QC1-999
Abstract

A global heat flux model based on a fractional derivative of plasma pressure is proposed for the heat transport in fusion plasmas. The degree of the fractional derivative of the heat flux, α, is defined through the power balance analysis of the steady state. The model was used to obtain the experimental values of α for a large database of the Joint European Torus (JET) carbon-wall as well as ITER like-wall plasmas. The fractional degrees of the electron heat flux are found to be α

Published
2020
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14. Wall conditions in WEST during operations with a new ITER grade, actively cooled divertor

Author

Gallo, A., Moreau, Ph., Douai, D., Alarcon, T., Afonin, K., Anzallo, V., Bisson, R., Bucalossi, J., Caprin, E., Corre, Y., De Combarieu, M., Desgranges, C., Devynck, P., Ekedahl, A., Fedorczak, N., Gaspar, J., Grosjean, A., Guillemaut, C., Guirlet, R., Gunn, J.P., Hillairet, J., Loarer, T., Maget, P., Manas, P., Morales, J., Pellissier, F.P., Tsitrone, E., Krieger, K., Hakola, A., and Widdowson, A.

Published
2024
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17. Conceptual design of the LHCD system on CFETR

Author

Liu, Liang, Yang, Yong, Li, Miaohui, Zhao, Lianmin, Ma, Wendong, Zhou, Tai'an, Liu, Chengzhou, Cheng, Min, Wang, Mao, Shan, Jiafang, Ding, Bojiang, Wu, Qiuran, Hillairet, Julien, Goniche, Marc, Peysson, Yves, Ekedahl, Annika, Wallace, Greg, Baek, Seung-Gyou, and Bonoli, Paul

Published
2023
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18. Overview of HL-2A recent experiments

Author

Xu, M, Duan, XR, Liu, Yi, Song, XM, Liu, DQ, Wang, YQ, Lu, B, Yang, QW, Zheng, GY, Ding, XT, Dong, JQ, Hao, GZ, Zhong, WL, Shi, ZB, Yan, LW, Zou, XL, Liu, YQ, Chen, W, Xiao, GL, Zhang, YP, Jiang, M, Hou, YM, Cheng, J, Liang, AS, Bai, XY, Cao, JY, Cao, Z, Chen, HT, Cui, CH, Cui, ZY, Delpech, L, Diamond, PH, Ekedahl, A, Feng, BB, Giruzzi, G, Gong, SB, He, HM, Hoang, T, Huang, M, Huang, Y, Ida, K, Inagaki, S, Isobe, M, Itoh, K, Itoh, S-I, Ji, XQ, Ke, R, Kobayashi, M, Lei, GJ, Li, B, Li, GS, Li, HJ, Li, JQ, Li, Q, Li, Qing, Li, XD, Li, YG, Li, Yongge, Mao, WC, Mazon, D, Mckee, GR, Morita, S, Nie, L, Peng, JF, Peysson, Y, Rao, J, Ren, Y, Tynan, GR, Wang, HX, Wang, QM, Wei, HL, Xia, F, Xiao, XP, Xuan, WM, Yan, Z, Yao, K, Yu, LM, Yu, Y, Yu, DL, Yuan, BD, Yuan, BS, Zhang, JH, Zhou, Y, and Liu, Yong

Subjects
magnetic fusion, overview, HL-2A tokamak, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Fluids & Plasmas
Abstract

The mission of HL-2A is to explore the key physical topics relevant to ITER and to the advanced tokamak operation (e.g. the operation of future HL-2M), such as the access of H-mode, energetic particle physics, edge-localized mode (ELM) mitigation/suppression and disruption mitigation. Since the 2016 Fusion Energy Conference, the HL-2A team has focused on the investigations on the following areas: (i) pedestal dynamics and L-H transition, (ii) techniques of ELM control, (iii) turbulence and transport, (iv) energetic particle physics. The HL-2A results demonstrated that the increase of mean shear flow plays a key role in triggering L-I and I-H transitions, while the change of flow is mainly induced by the ion pressure gradient. Both mitigation and suppression of ELMs were realized by laser blow-off seeded impurity (Al, Fe, W). The 30% Ne mixture supersonic molecular beam injection seeding also robustly induced ELM mitigation. The ELMs were mitigated by low-hybrid current drive. The stabilization of m/n = 1/1 ion fishbone activities by electron cyclotron resonance heating was found on the HL-2A. A new m/n = 2/1 ion fishbone activity was observed recently, and the modelling indicated that passing fast ions dominantly contribute to the driving of 2/1 fishbone. The non-linear coupling between the toroidal Alfven eigenmode and tearing mode (TM) led to the generation of a high frequency mode with the toroidal mode number n = 0. The turbulence was modulated by TM when the island width exceeds a threshold and the modulation is localized merely in the inner area of the islands. Meanwhile, turbulence radial spread took place across the island region.

Published
2019

19. Recent advances in EAST physics experiments in support of steady-state operation for ITER and CFETR

Author

Wan, BN, Liang, Y, Gong, XZ, Xiang, N, Xu, GS, Sun, Y, Wang, L, Qian, JP, Liu, HQ, Zeng, L, Zhang, L, Zhang, XJ, Ding, BJ, Zang, Q, Lyu, B, Garofalo, AM, Ekedahl, A, Li, MH, Ding, F, Ding, SY, Du, HF, Kong, DF, Yu, Y, Yang, Y, Luo, ZP, Huang, J, Zhang, T, Zhang, Y, Li, GQ, Xia, TY, Wan, Baonian, Li, Jiangang, Wan, Yuanxi, Song, Yuntao, Zhang, Xiaodong, Fu, Peng, Guo, Houyang, Liang, Yunfeng, Gong, Xianzhu, Xu, Guosheng, Xiao, Bingjia, Wu, Yu, Gao, Xiang, Yao, Damao, Xiang, Nong, Hu, Liqun, Shan, Jiafang, Zhao, Yanping, Luo, Guangnan, Hu, Chundong, Wu, Jiefeng, Hu, Jiansheng, Shen, Biao, Ji, Zhenshan, Gao, Ge, Huang, Yiyun, Xu, Liuwei, Zhang, Qiyong, Zhuang, Ming, Liu, Fukun, Zhao, Junyu, Chen, Junling, Cao, Bin, Cao, Lei, Chang, Jiafeng, Chen, Kaiyun, Chen, Ran, Chen, Yebin, Cheng, Anyi, Cheng, Yong, Dai, Yu, Deng, Wei, Deng, Xu, Ding, Bojiang, Ding, Fang, Ding, Rui, Ding, Siye, Du, Shijun, Duan, Yanmin, Feng, Jianqiang, Gan, Kaifu, Gao, Daming, Gao, Qingsheng, Gao, Wei, Gu, Yongqi, Guo, Yong, Han, Xiaofeng, Hu, Ailan, Hu, Chang, Hu, Guanghai, Hu, Huaichuan, Hu, Liangbin, Hu, Qingsheng, Hu, Yanlan, Hu, Zhenhua, Huang, Juan, Huang, Liansheng, Huang, Ming, Huang, Ronglin, and Ji, Xiang

Subjects
steady state, long pulse, high bootstrap current fraction, tokamak, Fluids & Plasmas, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Published
2019

23. Ion cyclotron resonance heating systems upgrade toward high power and CW operations in WEST

Author

Hillairet, Julien, Mollard, Patrick, Zhao, Yanping, Bernard, Jean-Michel, Song, Yuntao, Argouarch, Arnaud, Berger-By, Gilles, Charabot, Nicolas, Chen, Gen, Chen, Zhaoxi, Colas, Laurent, Delaplanche, Jean-Marc, Dumortier, Pierre, Durodié, Frédéric, Ekedahl, Annika, Fedorczak, Nicolas, Ferlay, Fabien, Goniche, Marc, Hatchressian, Jean-Claude, Helou, Walid, Jacquot, Jonathan, Joffrin, Emmanuel, Litaudon, Xavier, Lombard, Gilles, Maggiora, Riccardo, Magne, Roland, Milanesio, Daniele, Patterlini, Jean-Claude, Prou, Marc, Verger, Jean-Marc, Volpe, Robert, Vulliez, Karl, Wang, Yongsheng, Winkler, Konstantin, Yang, Qingxi, and Yuan, Shuai

Subjects
Physics - Plasma Physics, Physics - Instrumentation and Detectors
Abstract

The design of the WEST (Tungsten-W Environment in Steady-state Tokamak) Ion cyclotron resonance heating antennas is based on a previously tested conjugate-T Resonant Double Loops prototype equipped with internal vacuum matching capacitors. The design and construction of three new WEST ICRH antennas are being carried out in close collaboration with ASIPP, within the framework of the Associated Laboratory in the fusion field between IRFM and ASIPP. The coupling performance to the plasma and the load-tolerance have been improved, while adding Continuous Wave operation capability by introducing water cooling in the entire antenna. On the generator side, the operation class of the high power tetrodes is changed from AB to B in order to allow high power operation (up to 3 MW per antenna) under higher VSWR (up to 2:1). Reliability of the generators is also improved by increasing the cavity breakdown voltage. The control and data acquisition system is also upgraded in order to resolve and react on fast events, such as ELMs. A new optical arc detection system comes in reinforcement of the V r /V f and SHAD systems.

Published
2016
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24. Overview of recent HL-2A experiments

Author

Duan, XR, Liu, Yi, Xu, M, Yan, LW, Xu, Y, Song, XM, Dong, JQ, Ding, XT, Chen, LY, Lu, B, Liu, DQ, Rao, J, Xuan, WM, Yang, QW, Zheng, GY, Zou, XL, Liu, YQ, Zhong, WL, Zhao, KJ, Ji, XQ, Mao, WC, Wang, QM, Li, Q, Cao, JY, Cao, Z, Lei, GJ, Zhang, JH, Li, XD, Bai, XY, Cheng, J, Chen, W, Cui, ZY, Delpech, L, Diamond, PH, Dong, YB, Ekedahl, A, Hoang, T, Huang, Y, Ida, K, Itoh, K, Itoh, S-I, Isobe, M, Inagaki, S, Mazon, D, Morita, S, Peysson, Y, Shi, ZB, Wang, XG, Xiao, GL, Yu, DL, Yu, LM, Zhang, YP, Zhou, Y, Cui, CH, Feng, BB, Huang, M, Li, YG, Li, B, Li, GS, Li, HJ, Li, Qing, Peng, JF, Wang, YQ, Yuan, BS, and Liu, Yong

Subjects
tokamak, plasma physics, HL-2A, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Fluids & Plasmas
Published
2017

25. AI-Hot mot demokratin : En tematisk innehållsanalys av befintliga och potentiella hot mot demokratin, maktfördelning samt eventuella lösningar

Author

Ekedahl, Marika and Ekedahl, Marika

Abstract

I takt med den snabba digitaliserade utvecklingen och den utbredda användningen av teknikenförändras samhällets sätt att söka information, interagera samt hur beslut tas med mera. Det nya sättet att leva tillsammans med olika tekniker som utnyttjas för att manipulera användare genom att använda deras data som skapa falsk information är några att de faktorer som har påverkan på demokratin. Denna uppsats undersöker utifrån 12 artiklar en del av de faktorer som påverkar demokratin och vilka lösningar som diskuteras. Uppsatsen är utformad enligt tematisk innehållsanalys. De teman som identifierades var i trekodkategorier: Maktbalans, Påverkan och Lösningar. Under dessa finns undergrupper av teman, hädanefter kallad koder. Maktbalans har koderna Företagens makt, Utvecklarnas och teknikens makt samt Maktförskjutning. Under Påverkan finns koderna Valpåverkan, Påverkan på demokratiskt styre och processuell demokrati, neurologisk och beteende påverkan samt Nyhetspåverkan. Processuell demokrati avser beslutsprocesser genomförs och säkerställer delaktighet och rättvisa i dem. Under Lösningar finns koderna Etik & Norm, Utbildning samt lagregleringar. Alla artiklarna visade på påverkan på demokrati. I två av artiklar fanns dock tveksamhet ifallomfattningen är så stor att man behöver oroa sig. Resterande artiklar visar på stor påverkan och att någon slags lösning behövs i vissa områden.

Published
2024

26. Influencers personaförändring : En retorisk analys av Isabella Löwengrip och Joakim Lundells förändrade persona på Instagram

Author

Ekedahl, Sanna and Ekedahl, Sanna

Abstract

Influencers wield significant influence over their followers, making it essential to study how they build trust. This paper investigates how influencers Isabella Löwengrip, formerly Blondinbella, and Joakim Lundell, formerly Jockiboi, retained their followers' trust on Instagram during their persona changes. Given Instagram's popularity in Sweden, understanding influencer trust-building is crucial. Using rhetorical analysis, I will examine their official Instagram accounts to identify the strategies they used to maintain trust despite their identity transformations. Online, individuals often adopt identities with enhanced traits, different from their offlineidentity. Existing research reveals a gap in understanding influencers’ persona changes on Instagram. Relevant studies focus on parasocial relationships, online identities, and authenticity. Parasocial relationships involve perceived interactions between media users and figures, fostering identification. Online identities highlight favorable traits, differing from offline personas, while authenticity refers to perceived genuineness. This study aims to bridge this gap by exploring how influencers maintain trust during persona changes, making it a valuable research topic.

Published
2024

28. Evidens, barndom och makt i ett digitalt skifte : En kvalitativ innehållsanalys av riksdagsdebatten om en digital förskola

Author

Ekedahl, Julia, Sollerman, Elin, Ekedahl, Julia, and Sollerman, Elin

Abstract

Studien undersöker den politiska debatten om digitalisering i förskolan. Syftet är attsynliggöra de argument som används samt vad det säger om synen på barn, barndom ochförskolans roll. Studien ämnar belysa det skifte som skett inom förskolan där det under enfemårsperiod både presenterats ett införande och avvecklande av ett krav på digitalalärverktyg i förskolan. Detta skifte är angeläget att analysera eftersom det speglar vilken typav förskola, kunskap och syn på barn som framhävs av politiken samt hur detta ärföränderligt. För att analysera förskolans digitaliseringsskifte utgår studien från teorier ommakt, disciplin och barndomssociologi av Foucault, Jenks och Qvortrup. Studien utgår frånen kvalitativ innehållsanalys av riksdagsdebatter, statliga dokument och ett pressmeddelandefrån regeringen. Resultatet visar evidensens roll i politiken. Vid införandet avdigitaliseringskravet i förskolan framfördes evidens om digitaliseringens fördelar för enlikvärdig utbildning. Vid avvecklandet av kravet presenterades istället evidens om hurdigitalisering hämmar barns lärande. Den evidens som lyfts varierar beroende på vilkenkunskap den sittande regeringen premierar, vilket förklaras genom Foucaults teorier om maktoch kunskap. Vidare visar resultatet att politikens argument reflekterar en tvådelad syn påbarn och barndom vilket återfunnits parallellt och oberoende av tid. Barn anses ha ett värdehär och nu samtidigt som de även beskrivs som en investering i samhället, vilket förklarasmed hjälp av Qvortrups begreppsliga ramverk. Synen på barn och barndom relateras även tillförskolans roll som disciplinerande och central för formandet av framtida medborgare.Förskolans disciplinerande roll uppfattas hotad vilket resulterar i att en traditionell utbildningeftersträvas där böcker anses vara lämpligare än digitala lärverktyg. Denna förändringförklaras genom Foucaults och Jenks teorier om disciplin och övervakning. Studien fokuserarsåledes på vilken evidens politiken väljer att stödj

Published
2024

29. En studie om hur elever som är bekanta med Blockmodellen väljer att lösa textuppgifter

Author

Rehnholm, Olivia, Ekedahl, Sara, Rehnholm, Olivia, and Ekedahl, Sara

Abstract

Blockmodellen är en visuell metod som används inom matematik vid arbete med problemlösning och textuppgifter. Metoden utvecklades i Singapore på 1980-talet och har sedan dess visats vara framgångsrik inom matematik. Dess framgång har gjort att den spridits internationellt och även används i svenska skolor. Syftet med studien är att bidra med kunskap om hur elever i årskurs 2 som är bekanta med Blockmodellen väljer att lösa textuppgifter. Syftet uppfylls genom två frågeställningar som berör vilken metod eleverna använder, samt vad som påverkar deras val av metod. Studien genomfördes i två olika klasser med totalt 36 elever. Samtliga elever fick ett antal textuppgifter att lösa och utifrån elevlösningarna valdes tio elever ut för individuella intervjuer. Materialet analyserades utifrån tematisk analys. Studien visar att elever väljer att använda olika metoder för att lösa textuppgifter trots att de är bekanta med Blockmodellen. Vid de individuella intervjuerna framkom det att eleverna valde, enligt dem, den effektivaste metoden för att lösa uppgiften. Eleverna beskrev Blockmodellen som tidskrävande men samtidigt hjälpsam. Genom att använda blocken får de syn på vad som finns, vad som saknas och vad som söks i uppgiften. En slutsats är att elevernas val av metod varierar vilket tyder på att eleverna har olika preferenser när det gäller vilken metod de väljer att använda vid arbete med textuppgifter., The Bar Model is a visual method used in mathematics when working with problem- solving and word problems. The method was developed in Singapore in the 1980s and has since been shown to be successful in mathematics. Its success has led to its international spread and is now used in Swedish schools as well. The aim of the study is to contribute knowledge about how students in second grade who are familiar with the Bar Model choose to solve word problems. The aim is answered through two questions that concern which method the students use and what influences their choice of method. The study was conducted in two different classes with a total of 36 students. All students were given several word problems to solve and based on the student solutions, ten of the students were selected for individual interviews. Thematic analysis was used to analyze the material. The study show that students choose to use different methods to solve word problems despite being familiar with the Bar Model. During the individual interviews, it emerged that the students chose what they considered to be the most effective method for problem solving. The student describer the Bar Model Bar Model as time-consuming but also helpful. By using the bars, they could see what is present, what is missing and what is being sought. One conclusion is that students' choice of method varies, indicating that they have different preferences regarding which method to use for solving word problems.

Published
2024

30. Vardagens aktiviteter och möjligheten till en meningsfull fritid hos ungdomar vars syskon har Downs syndrom

Author

Bye Ekedahl, Marianne, Paridon, Frida, Bye Ekedahl, Marianne, and Paridon, Frida

Abstract

Bakgrund: Familjen påverkas på olika sätt när ett barn med funktionsnedsättning föds. Det ökade omvårdnadsbehovet som barnet med Downs Syndrom kan ha gör att normtypiska syskon kan få påverkan på sina vardagsaktiviteter. Detta då mer av föräldrarnas tid läggs på barnet med Downs syndrom. Syfte: Syftet med studien är att undersöka vardagens aktiviteter och möjligheten till en meningsfull fritid hos ungdomar vars syskon har Downs Syndrom. Metod: En kvalitativ intervjustudie med induktiv ansats med fyra ungdomar och deras föräldrar. Resultat: Ungdomarna har en aktiv vardag med meningsfulla fritidsintressen. Förutsättningarna för denna vardag är bland annat planering och samarbete inom familjen. Ungdomarnas fritid är en källa till glädje, ger utlopp för kreativitet samt möjligheten att förbättra förmågor. Slutsats: Att ha ett syskon med Downs Syndrom behöver inte betyda en påverkan på möjligheten till deltagande i meningsfulla aktiviteter för familjens normtypiska ungdomar. Tack vare engagerade vårdnadshavare och avlastning från samhället kan familjens normtypiska ungdomar ha en aktiv vardag. Mer forskning behövs kring vilka förutsättningar och faktorer som möjliggör en aktiv vardag., Background: Families are affected in different ways when a child with impairments is born. The increased caring need that the child with Down Syndrome may have, means that normtypical siblings’ everyday activities might be affected. This, because more of the parents' time is spent on the child with Down Syndrome. Aim: The purpose of the study is to investigate everyday activities and the possibility of meaningful leisuretime in adolescents whose siblings have Down Syndrome. Method: A qualitative interwievstudy with an inductive approach with four adolescents and their parents. Result: The adolescents have an active everyday life with meaningful leisure interests. The basis for this everyday life include planning and cooperation within the family. The adolescents free time is a source of joy, an outlet for creativity and an opportunity to improve skills. Conclusion: Having a sibling with Down syndrome doesn´t automatically mean an impact on the opportunity to participate in meaningful activities for the family's normtypical adolescents. Thanks to committed parents and help from society, the family's normtypical adolescents can have an active everyday life. More research is needed into which conditions and factors enable an active everyday life.

Published
2024

31. Design and RF measurements of a 5 GHz 500 kW window for the ITER LHCD system

Author

Hillairet, Julien, Achard, J., Dechambre, N., Delpech, L., Ekedahl, A., Faure, N., Goniche, M., Kim, J., Larroque, S., Magne, R., Marfisi, L., Namkung, W., Park, H., Park, S., Poli, S., and Vulliez, K.

Subjects
Physics - Plasma Physics, Physics - Instrumentation and Detectors
Abstract

CEA/IRFM is conducting R\&D efforts in order to validate the critical RF components of the 5 GHz ITER LHCD system, which is expected to transmit 20 MW of RF power to the plasma. Two 5 GHz 500 kW BeO pill-box type window prototypes have been manufactured in 2012 by the PMB Company, in close collaboration with CEA/IRFM. Both windows have been validated at low power, showing good agreement between measured and modeling, with a return loss better than 32 dB and an insertion loss below 0.05 dB. This paper reports on the window RF design and the low power measurements. The high power tests up to 500kW have been carried out in March 2013 in collaboration with NFRI. Results of these tests are also reported. In the current ITER LHCD design, 20 MW Continuous Wave (CW) of Radio-Frequency power at 5 GHz are expected to be generated and transmitted to the plasma. In order to separate the vacuum vessel pressure from the cryostat waveguide pressure, forty eight 5 GHz 500kW CW windows are to be assembled on the waveguides at the equatorial port flange. For nuclear safety reasons, forty eight additional windows could be located in the cryostat section, to separate and monitor the cryostat waveguide pressure from the exterior transmission line pressure. These windows are identified as being one of the main critical components for the ITER LHCD system since first ITER LHCD studies [1] [2] [3] or more recently [4] [5] , and clearly require an important R\&D effort. In this context and even if the LHCD system is not part of the construction baseline, the CEA/IRFM is conducting a R\&D effort in order to validate a design and the performances of these RF windows. In order to begin the assessment of this need, two 5 GHz 500 kW/5 s pill-box type windows prototypes have been manufactured in 2012 by the PMB Company in close collaboration with the CEA/IRFM [6]. The section 2 of this paper reports the RF and mechanical design of a 5 GHz window. Some features of the mechanical design and the experimental RF measurements at low power are reported in section 3. High power results, made in collaboration with NFRI, are detailed in section 4. The development of CW windows is discussed in the conclusion. 2-RF AND MECHANICAL DESIGN The proposed 5 GHz RF window is based on a pill-box design [2] , i.e. a ceramic brazed in portion of a circular waveguide, connected on either side to a rectangular waveguide section. Typical design rules of thumb of such device are circular section diameter about the same size of the diagonal of the rectangular waveguide (cf. FIGURE 1). Without taking into account the ceramic, the circular section length is approximately half a guided wavelength of the circular TE 11 mode, in order for the device to act as a half-wave transformer. Once optimized, taking into account the ceramic, matching is correct only for a narrow band of frequency and is very sensitive to the device dimensions and the ceramic relative permittivity. The heat losses in the ceramic, which have to be extracted by an active water cooling, depends on the inside electric field topology and of ceramic dielectric loss (loss tangent). Undesirable modes due to parasitic resonances can be excited in the ceramic volume, raising the electric field and, Comment: 20th Topical Conference on Radio Frequency Power in Plasmas, Jun 2013, Sorrento, Italy. 2014

Published
2015
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32. Recent progress on lower hybrid current drive and implications for ITER

Author

Hillairet, Julien, Ekedahl, A., Goniche, M., Achard, J., Armitano, A., Beckett, B., Belo, J., Berger-By, G., Corbel, E., Delpech, L., Decker, J., Dumont, R., Guilhem, D., Kazarian, F., Litaudon, X., Magne, R., Marfisi, L., Mollard, P., Namkung, W., Nilsson, E., Park, S., Peysson, Y., Preynas, M., Sharma, P. K., Prou, M., and Team, Tore Supra

Subjects
Physics - Plasma Physics
Abstract

The sustainment of steady-state plasmas in tokamaks requires efficient current drive systems. Lower Hybrid Current Drive (LHCD) is currently the most efficient method to generate a continuous additional off-axis toroidal plasma current as well as reduce the poloidal flux consumption during the plasma current ramp-up phase. The operation of the Tore Supra ITER-like LH launcher has demonstrated the capability to couple LH power at ITER-like power densities with very low reflected power during long pulses. In addition, the installation of eight 700kW/CW klystrons at the LH transmitter has allowed increasing the total LH power in long pulse scenarios. However, in order to achieve pure stationary LH sustained plasmas, some R\&D are needed to increase the reliability of all the systems and codes, from the RF sources to the plasma scenario prediction. The CEA/IRFM is addressing some of these issues by leading a R\&D program towards an ITER LH system and by the validation of an integrated LH modeling suite of codes. In 2011, the RF design of a mode converter has been validated at low power. A 500 kW/5 s RF window is currently under manufacturing and will be tested at high power in 2012 in collaboration with NFRI. All of this work aims to reduce the operational risks associated with the ITER steady-state operations.

Published
2015
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33. Lower Hybrid antennas for nuclear fusion experiments

Author

Hillairet, Julien, Achard, J., Bae, Young-Soon, Bai, X., Balorin, C., Baranov, Y., Basiuk, V., Bécoulet, A., Belo, J., Berger-By, G., Brémond, S., Castaldo, C., Ceccuzzi, S., Cesario, R., Corbel, E., Courtois, X., Decker, J., Delmas, E., Delpech, L., Ding, X., Douai, D., Ekedahl, A., Goletto, C., Goniche, M., Guilhem, D., Hertout, P., Imbeaux, F., Litaudon, X., Magne, R., Mailloux, J., Mazon, D., Mirizzi, F., Mollard, P., Moreau, P., Oosako, T., Petrzilka, V., Peysson, Y., Poli, S., Preynas, M., Prou, M., Saint-Laurent, F., Samaille, F., and Saoutic, B.

Subjects
Physics - Plasma Physics
Abstract

The nuclear fusion research goal is to demonstrate the feasibility of fusion power for peaceful purposes. In order to achieve the conditions similar to those expected in an electricity-generating fusion power plant, plasmas with a temperature of several hundreds of millions of degrees must be generated and sustained for long periods. For this purpose, RF antennas delivering multi-megawatts of power to magnetized confined plasma are commonly used in experimental tokamaks. In the gigahertz range of frequencies, high power phased arrays known as "Lower Hybrid" (LH) antennas are used to extend the plasma duration. This paper reviews some of the technological aspects of the LH antennas used in the Tore Supra tokamak and presents the current design of a proposed 20 MW LH system for the international experiment ITER.

Published
2015
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34. Calorimetry measurement for the energy balance and energy distribution in West for L-mode plasmas

Author

Gaspar, Jonathan, primary, Gerardin, Jonathan, additional, Corre, Yann, additional, Daumas, Jeremy, additional, Fedorczak, Nicolas, additional, Lamaison, Valérie, additional, Bourdelle, Clarisse, additional, Ciraolo, Guido, additional, Ekedahl, Annika, additional, Gallo, Alberto, additional, Rivals, Nicolas, additional, and Tsitrone, Emmanuelle, additional

Published
2024
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36. Overview of the Recent Study on ELM Mitigation Physics with Different External Actuators on HL-2A Tokamak

Author

Xiao, G. L., Zhong, W. L., Zhang, Y. P., Zou, X. L., Liang, A. S., Feng, B. B., Bai, X. Y., Zhang, K., Mazon, D., Chen, C. Y., Chen, W., Cheng, J., Delpech, L., Ding, X. T., Dong, C. F., Dong, J. Q., Cui, Z. Y., Ekedahl, A., Gao, J. M., Giruzzi, G., Goniche, M., Han, M. K., He, X. X., Hoang, T., Huang, Z. H., Isobe, M., Ji, X. Q., Li, Y. G., Liu, A. D., Liu, C. H., Liu, L., Lu, B., Peysson, Y., Shi, P. W., Song, X. M., Sun, P., Wang, T. B., Wang, Z. H., Wang, Z. X., Wen, J., Xiao, W. W., Yan, L. W., Yang, Z. C., Yu, D. L., Yuan, G. L., Zhang, P. F., Zhou, Y., Shi, Z. B., Liu, Y., Yang, Q. W., Xu, M., and Duan, X. R.

Published
2020
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39. Novel functional proteins coded by the human genome discovered in metastases of melanoma patients

Author

Sanchez, Aniel, Kuras, Magdalena, Murillo, Jimmy Rodriguez, Pla, Indira, Pawlowski, Krzysztof, Szasz, A. Marcell, Gil, Jeovanis, Nogueira, Fábio C. S., Perez-Riverol, Yasset, Eriksson, Jonatan, Appelqvist, Roger, Miliotis, Tasso, Kim, Yonghyo, Baldetorp, Bo, Ingvar, Christian, Olsson, Håkan, Lundgren, Lotta, Ekedahl, Henrik, Horvatovich, Peter, Sugihara, Yutaka, Welinder, Charlotte, Wieslander, Elisabet, Kwon, Ho Jeong, Domont, Gilberto B., Malm, Johan, Rezeli, Melinda, Betancourt, Lazaro Hiram, and Marko-Varga, György

Published
2020
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40. Operation and coupling of LH waves with the ITER-like wall at JET

Author

Kirov, K K, Mailloux, J, Ekedahl, A, Petrzilka, V, Arnoux, G, Baranov, Yu, Brix, M, Goniche, M, Jachmich, S, Mayoral, M-L, Ongena, J, Rimini, F, Stamp, M, and Contributors, JET EFDA

Subjects
Physics - Plasma Physics
Abstract

In this paper important aspects of Lower Hybrid (LH) operation with the ITER Like Wall (ILW) [1] at JET are reported. Impurity release during LH operation was investigated and it was found that there is no significant Be increase with LH power. Concentration of W was analysed in more detail and it was concluded that LH contributes negligibly to its increase. No cases of W accumulation in LH-only heating experiments were observed so far. LH wave coupling was studied and optimised to achieve the level of system performance similar to before ILW installation. Measurements by Li-beam were used to study systematic dependencies of the SOL density on the gas injection rate from a dedicated gas introduction module and the LH power and launcher position. Experimental results are supported by SOL transport modelling. Observations of arcs in front of the LH launcher and hotspots on magnetically connected sections of the vessel are reported. Overall, a relatively troublefree operation of the LH system up to 2.5MW of coupled Radio Frequency (RF) power in L-mode plasma was achieved with no indication that the power cannot be increased further., Comment: 21 pages, 9 figures. This is an author-created, un-copyedited version of an article accepted for publication in Plasma Physics & Controlled Fusion. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it

Published
2013
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44. Moduli and periods of simply connected Enriques surfaces

Author

Ekedahl, T., Hyland, J. M. E., and Shepherd-Barron, N. I.

Subjects
Mathematics - Algebraic Geometry, 14D23, 14J10
Abstract

We describe a period map for those simply connected Enriques surfaces in characteristic 2 whose canonical double cover is K3. The moduli stack for these surfaces has a Deligne-Mumford quotient that is an open substack of a $\mathbb P^1$-bundle over the period space. We also give some general results relating local and global moduli for algebraic varieties and describe the difference in their dimensions in terms of the failure of the automorphism group scheme to be reduced.

Published
2012

45. Cycle classes on the moduli of K3 surfaces in positive characteristic

Author

Ekedahl, Torsten and van der Geer, Gerard

Subjects
Mathematics - Algebraic Geometry, 14C17, 14J28, 14H10
Abstract

This paper provides explicit closed formulas in terms of tautological classes for the cycle classes of the height and Artin invariant strata in families of K3 surfaces. The proof is uniform for all strata and uses a flag space as the computations in [arXiv:math/0412272] for the Ekedahl-Oort strata for families of abelian varieties, but employs a Pieri formula formula to determine the push down to the base space., Comment: 34 pages, latex; version revised by second author; to appear in Selecta Math

Published
2011

46. The human melanoma proteome atlas—Defining the molecular pathology

Author

Lazaro Hiram Betancourt, Jeovanis Gil, Yonghyo Kim, Viktória Doma, Uğur Çakır, Aniel Sanchez, Jimmy Rodriguez Murillo, Magdalena Kuras, Indira Pla Parada, Yutaka Sugihara, Roger Appelqvist, Elisabet Wieslander, Charlotte Welinder, Erika Velasquez, Natália Pinto deAlmeida, Nicole Woldmar, Matilda Marko‐Varga, Krzysztof Pawłowski, Jonatan Eriksson, Beáta Szeitz, Bo Baldetorp, Christian Ingvar, Håkan Olsson, Lotta Lundgren, Henrik Lindberg, Henriett Oskolas, Boram Lee, Ethan Berge, Marie Sjögren, Carina Eriksson, Dasol Kim, Ho Jeong Kwon, Beatrice Knudsen, Melinda Rezeli, Runyu Hong, Peter Horvatovich, Tasso Miliotis, Toshihide Nishimura, Harubumi Kato, Erik Steinfelder, Madalina Oppermann, Ken Miller, Francesco Florindi, Qimin Zhou, Gilberto B. Domont, Luciana Pizzatti, Fábio C. S. Nogueira, Peter Horvath, Leticia Szadai, József Tímár, Sarolta Kárpáti, A. Marcell Szász, Johan Malm, David Fenyö, Henrik Ekedahl, István Balázs Németh, and György Marko‐Varga

Subjects
heterogeneity, histopathology, metastatic malignant melanoma, proteogenomics, subcellular localization, Medicine (General), R5-920
Abstract

Abstract The MM500 study is an initiative to map the protein levels in malignant melanoma tumor samples, focused on in‐depth histopathology coupled to proteome characterization. The protein levels and localization were determined for a broad spectrum of diverse, surgically isolated melanoma tumors originating from multiple body locations. More than 15,500 proteoforms were identified by mass spectrometry, from which chromosomal and subcellular localization was annotated within both primary and metastatic melanoma. The data generated by global proteomic experiments covered 72% of the proteins identified in the recently reported high stringency blueprint of the human proteome. This study contributes to the NIH Cancer Moonshot initiative combining detailed histopathological presentation with the molecular characterization for 505 melanoma tumor samples, localized in 26 organs from 232 patients.

Published
2021
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47. The Human Melanoma Proteome Atlas—Complementing the melanoma transcriptome

Author

Lazaro Hiram Betancourt, Jeovanis Gil, Aniel Sanchez, Viktória Doma, Magdalena Kuras, Jimmy Rodriguez Murillo, Erika Velasquez, Uğur Çakır, Yonghyo Kim, Yutaka Sugihara, Indira Pla Parada, Beáta Szeitz, Roger Appelqvist, Elisabet Wieslander, Charlotte Welinder, Natália Pinto deAlmeida, Nicole Woldmar, Matilda Marko‐Varga, Jonatan Eriksson, Krzysztof Pawłowski, Bo Baldetorp, Christian Ingvar, Håkan Olsson, Lotta Lundgren, Henrik Lindberg, Henriett Oskolas, Boram Lee, Ethan Berge, Marie Sjögren, Carina Eriksson, Dasol Kim, Ho Jeong Kwon, Beatrice Knudsen, Melinda Rezeli, Johan Malm, Runyu Hong, Peter Horvath, A. Marcell Szász, József Tímár, Sarolta Kárpáti, Peter Horvatovich, Tasso Miliotis, Toshihide Nishimura, Harubumi Kato, Erik Steinfelder, Madalina Oppermann, Ken Miller, Francesco Florindi, Quimin Zhou, Gilberto B. Domont, Luciana Pizzatti, Fábio C. S. Nogueira, Leticia Szadai, István Balázs Németh, Henrik Ekedahl, David Fenyö, and György Marko‐Varga

Subjects
acetylation stoichiometry, BRAF, driver mutations, histopathology, metastatic melanoma, phosphorylation, Medicine (General), R5-920
Abstract

Abstract The MM500 meta‐study aims to establish a knowledge basis of the tumor proteome to serve as a complement to genome and transcriptome studies. Somatic mutations and their effect on the transcriptome have been extensively characterized in melanoma. However, the effects of these genetic changes on the proteomic landscape and the impact on cellular processes in melanoma remain poorly understood. In this study, the quantitative mass‐spectrometry‐based proteomic analysis is interfaced with pathological tumor characterization, and associated with clinical data. The melanoma proteome landscape, obtained by the analysis of 505 well‐annotated melanoma tumor samples, is defined based on almost 16 000 proteins, including mutated proteoforms of driver genes. More than 50 million MS/MS spectra were analyzed, resulting in approximately 13,6 million peptide spectrum matches (PSMs). Altogether 13 176 protein‐coding genes, represented by 366 172 peptides, in addition to 52 000 phosphorylation sites, and 4 400 acetylation sites were successfully annotated. This data covers 65% and 74% of the predicted and identified human proteome, respectively. A high degree of correlation (Pearson, up to 0.54) with the melanoma transcriptome of the TCGA repository, with an overlap of 12 751 gene products, was found. Mapping of the expressed proteins with quantitation, spatiotemporal localization, mutations, splice isoforms, and PTM variants was proven not to be predicted by genome sequencing alone. The melanoma tumor molecular map was complemented by analysis of blood protein expression, including data on proteins regulated after immunotherapy. By adding these key proteomic pillars, the MM500 study expands the knowledge on melanoma disease.

Published
2021
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48. Approximating classifying spaces by smooth projective varieties

Author

Ekedahl, Torsten

Subjects
Mathematics - Algebraic Geometry, Mathematics - Algebraic Topology, 55R40, 14L24, 14F25
Abstract

We prove that for every reductive algebraic group $H$ with centre of positive dimension and every integer $K$ there is a smooth and projective variety $X$ and an algebraic $H$-torsor $P \to X$ such that the classifying map $X \to \Bclass H$ induces an isomorphism in cohomology in degrees $\le K$. This is then applied to show that if $G$ is a connected non-special group there is a $G$-torsor $P \to X$ for which we do not have $[P]=[G][X]$ in the (completion of the) Grothendieck ring of varieties., Comment: 9 pages

Published
2009

49. A geometric invariant of a finite group

Author

Ekedahl, Torsten

Subjects
Mathematics - Algebraic Geometry, 20D99, 14L30
Abstract

We study the class of the classifying stack of a finite group in a Grothendieck group of algebraic stacks introduced previously. We show that this class is trivial in a number of examples most notably for all symmetric groups. We also give some examples where it is not trivial. The latter uses counterexamples of Saltman and Swan to the problem of Noether., Comment: 23 pages

Published
2009

50. The Grothendieck group of algebraic stacks

Author

Ekedahl, Torsten

Subjects
Mathematics - Algebraic Geometry, 14A20, 14J10
Abstract

We introduce a Grothendieck group of algebraic stacks (with affine stabilisers) analogous to the Grothendieck group of algebraic varieties. We then identify it with a certain localisation of the Grothendieck group of algebraic varieties. Several invariants of elements in this group are discussed. The most important is an extension of the Euler characteristic (of cohomology with compact support) but in characteristic zero we introduce invariants which are able to distinguish between classes with the same Euler characteristic. These invariants are actually defined on the completed localised Grothendieck ring of varieties used in motivic integration. In particular we show that there are $\PSL_n$-torsors of varieties whose class in the completed localised Grothendieck ring of varieties is not the product of the class of the base and the class of $\PSL_n$., Comment: 21 pages; Two references have been added as well as a discussion of their relevance

Published
2009

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