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2. Nonlinear dynamics of energetic-particle driven geodesic acoustic modes in ASDEX Upgrade

Author

Novikau, I., Biancalani, A., Bottino, A., Lauber, Ph., Poli, E., Manz, P., Conway, G. D., Di Siena, A., Ohana, N., Lanti, E., Villard, L., and Team, ASDEX Upgrade

Subjects
Physics - Plasma Physics
Abstract

Turbulence in tokamaks generates radially sheared zonal flows. Their oscillatory counterparts, geodesic acoustic modes (GAMs), appear due to the action of the magnetic field curvature. The GAMs can be driven unstable by an anisotropic energetic particle (EP) population leading to the formation of global radial structures, called EGAMs. The EGAMs can redistribute EP energy to the bulk plasma through collisionless wave-particle interaction. In such a way, the EGAMs might contribute to the plasma heating. Thus, investigation of EGAM properties, especially in the velocity space, is necessary for precise understanding of the transport phenomena in tokamak plasmas. In this work, the nonlinear dynamics of EGAMs without considering the mode interaction with the turbulence is investigated with the help of a Mode-Particle-Resonance (MPR) diagnostic implemented in the global gyrokinetic particle-in-cell code ORB5. An ASDEX Upgrade discharge is chosen as a reference case for this investigation due to its rich EP nonlinear dynamics. An experimentally relevant magnetic field configuration, thermal species profiles and an EP density profile are taken for EGAM chirping modelling and its comparison with available empirical data. The same magnetic configuration is used to explore energy transfer by the mode from the energetic particles to the thermal plasma including kinetic electron effects. For a given EGAM level the plasma heating by the mode can be significantly enhanced by varying the EP parameters. Electron dynamics decreases the EGAM saturation amplitude and consequently reduces the plasma heating, even though the mode transfers its energy to thermal ions much more than to electrons.

Published
2019
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3. Linear gyrokinetic investigation of the geodesic acoustic modes in realistic tokamak configurations

Author

Novikau, I., Biancalani, A., Bottino, A., Conway, G. D., Gürcan, Ö. D., Manz, P., Morel, P., Poli, E., Di Siena, A., and Team, the ASDEX Upgrade

Subjects
Physics - Plasma Physics
Abstract

Geodesic acoustic modes (GAMs) are studied by means of the gyrokinetic global particle-in-cell code ORB5. Linear electromagnetic simulations in the low electron beta limit have been performed, in order to separate acoustic and Alfv\'enic time scales and obtain more accurate measurements. The dependence of the frequency and damping rate on several parameters such as the safety factor, the GAM radial wavenumber and the plasma elongation is studied. All simulations have been performed with kinetic electrons with realistic electron/ion mass ratio. Interpolating formulae for the GAM frequency and damping rate, based on the results of the gyrokinetic simulations, have been derived. Using these expressions, the influence of the temperature gradient on the damping rate is also investigated. Finally, the results are applied to the study of a real discharge of the ASDEX Upgrade tokamak.

Published
2017
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4. From L-mode to the L–H transition, experiments on ASDEX upgrade and related gyrokinetic simulations.

Author

Bonanomi, N., Angioni, C., Conway, G. D., Happel, T., Plank, U., Schneider, P. A., and Staebler, G. M.

Abstract

This work combines experimental observations from the ASDEX Upgrade tokamak with related gyrokinetic simulations of the turbulence moving from L-mode toward, and beyond, the L–H transition. Dedicated experiments have been performed with slow steps of increasing electron cyclotron heating power. Gyrokinetic simulations of the edge turbulence of these plasmas highlight the key roles of the non-linear electromagnetic effects and the external flow shear (E × B shear), both related to the evolution of the plasma pressure profile with increasing heating power. The increase in the plasma βe destabilizes turbulence at low toroidal mode numbers, that, in turn, is strongly suppressed by the external flow shear. This allows the plasma pressure profiles to evolve without a sharp rise in the turbulent fluxes. When all the experimentally measured plasma parameters are consistently included as inputs of the local gyrokinetic simulations, both the experimental electron and ion heat fluxes are quantitatively reproduced on the whole L-mode phase of the selected discharge. Simulations carried out with edge parameters of an ELM-free H-mode phase still show the importance of the mechanisms discussed earlier while also indicating possible limitations of the local approach. [ABSTRACT FROM AUTHOR]

Published
2024
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5. Experimental study of the edge radial electric field in different drift configurations and its role in the access to H-mode at ASDEX Upgrade

Author

Plank, U, Brida, D, Conway, G, Happel, T, Hubbard, A, Putterich, T, Angioni, C, Cavedon, M, Dux, R, Eich, T, Fischer, R, Hennequin, P, Plank U., Brida D., Conway G. D., Happel T., Hubbard A. E., Putterich T., Angioni C., Cavedon M., Dux R., Eich T., Fischer R., Hennequin P., Plank, U, Brida, D, Conway, G, Happel, T, Hubbard, A, Putterich, T, Angioni, C, Cavedon, M, Dux, R, Eich, T, Fischer, R, Hennequin, P, Plank U., Brida D., Conway G. D., Happel T., Hubbard A. E., Putterich T., Angioni C., Cavedon M., Dux R., Eich T., Fischer R., and Hennequin P.

Abstract

The formation of the equilibrium radial electric field (Er) has been studied experimentally at ASDEX Upgrade (AUG) in L-modes of "favorable"(ion ∇ B-drift toward primary X-point) and "unfavorable"(ion ∇ B-drift away from primary X-point) drift configurations, in view of its impact on H-mode access, which changes with drift configurations. Edge electron and ion kinetic profiles and impurity velocity and mean-field Er profiles across the separatrix are investigated, employing new and improved measurement techniques. The experimental results are compared to local neoclassical theory as well as to a simple 1D scrape-off layer (SOL) model. It is found that in L-modes of matched heating power and plasma density, the upstream SOL Er and the main ion pressure gradient in the plasma edge are the same for either drift configurations, whereas the Er well in the confined plasma is shallower in unfavorable compared to the favorable drift configuration. The contributions of toroidal and poloidal main ion flows to Er, which are inferred from local neoclassical theory and the experiment, cannot account for these observed differences. Furthermore, it is found that in the L-mode, the intrinsic toroidal edge rotation decreases with increasing collisionality and it is co-current in the banana-plateau regime for all different drift configurations at AUG. This gives rise to a possible interaction of parallel Pfirsch-Schlüter flows in the SOL with the confined plasma. Thus, the different H-mode power threshold for the two drift configurations cannot be explained in the same way at AUG as suggested by LaBombard et al. [Phys. Plasmas 12, 056111 (2005)] for Alcator C-Mod. Finally, comparisons of Er profiles in favorable and unfavorable drift configurations at the respective confinement transitions show that also the Er gradients are all different, which indirectly indicates a different type or strength of the characteristic edge turbulence in the two drift configurations.

Published
2023

6. Overview of L- to H-mode transition experiments at ASDEX Upgrade

Author

Plank, U, Mcdermott, R, Birkenmeier, G, Bonanomi, N, Cavedon, M, Conway, G, Eich, T, Griener, M, Grover, O, Schneider, P, Willensdorfer, M, Plank U., McDermott R. M., Birkenmeier G., Bonanomi N., Cavedon M., Conway G. D., Eich T., Griener M., Grover O., Schneider P. A., Willensdorfer M., Plank, U, Mcdermott, R, Birkenmeier, G, Bonanomi, N, Cavedon, M, Conway, G, Eich, T, Griener, M, Grover, O, Schneider, P, Willensdorfer, M, Plank U., McDermott R. M., Birkenmeier G., Bonanomi N., Cavedon M., Conway G. D., Eich T., Griener M., Grover O., Schneider P. A., and Willensdorfer M.

Abstract

This paper presents an overview of results from L-H transition experiments that were performed at ASDEX Upgrade (AUG) with the aim of identifying the underlying mechanisms leading to H-mode confinement. With a broad variety of experiments and new diagnostic techniques, as well as modeling efforts, AUG has contributed substantially to improving our understanding of the L-H transition over the past years. In this review, the important roles of the ion heat channel and the edge radial electric field (Er ) in the L-H transition physics are brought into context with known dependencies of the H-mode power threshold ( P L H ), such as the impact of wall material, magnetic perturbations, and the magnetic configuration. Furthermore, experimental and theoretical results obtained at AUG on the L-mode edge turbulence are connected to the mean-field Er and its related shear flow. This led to a deeper understanding of the I-phase plasma regime, has resolved the so-called isotope effect of P L H , and led to the development of a semi-analytical model that can describe AUG’s experimental observations of the L-H transition together with the L- and H-mode density limits.

Published
2023

7. A fully synthetic type-I ELM cycle diagnostic using conventional O-mode reflectometry.

Author

Vicente, J., Cathey, A., Silva, F. da, Heuraux, S., Hoelzl, M., and Conway, G. D.

Subjects
REFLECTOMETRY, MICROWAVE reflectometry, NUMERICAL integration, INFORMATION-seeking behavior, MAGNETOHYDRODYNAMICS
Abstract

Significant advances in modeling and simulations for microwave reflectometry have been conducted in recent years. An example is the integration of improved numerical descriptions of magneto-hydrodynamics (MHD) instabilities, obtained from MHD codes, together with 2D full-wave codes to implement synthetic reflectometry diagnostics in realistic conditions. In particular, the nonlinear MHD code JOREK has been used previously together with the 2D full-wave code REFMUL, to assess the response of conventional O-mode reflectometry along a Type-I edge localized mode (ELM) crash. In this work, a similar framework and synthetic diagnostic set-up are considered but with an extended MHD simulation where a Type-I ELM cycle comprised of several ELM crashes is studied. This includes the self-consistent MHD evolution along inter-ELM periods, which was absent in the previous study. The reflectometer response at the mid-plane of the low magnetic field side is used to provide information about the behavior of density fluctuations along the full ELM cycle. The inter-ELM periods display density fluctuations in agreement with the ELM triggering mechanisms manifesting as reflectometry signatures which are identified with ELM precursors. The precursor signatures are observed a few milliseconds before a transition from linear to non-linear reflectometry regimes occurs, associated with the explosive onset of the ELM. [ABSTRACT FROM AUTHOR]

Published
2023
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9. Isotope effects on energy transport in the core of ASDEX-Upgrade tokamak plasmas: Turbulence measurements and model validation.

Author

Molina Cabrera, P. A., Rodriguez-Fernandez, P., Görler, T., Bergmann, M., Höfler, K., Denk, S. S., Bielajew, R., Conway, G. D., Yoo, C., and White, A. E.

Subjects
TOKAMAKS, CYCLOTRONS, DEUTERIUM ions, PLASMA turbulence, TRITIUM, MODEL validation, FUSION reactors, ELECTRON configuration, LARMOR radius
Abstract

Design and operation of future tokamak fusion reactors using a deuterium–tritium 50:50 mix requires a solid understanding of how energy confinement properties change with ion mass. This study looks at how turbulence and energy transport change in L-mode plasmas in the ASDEX Upgrade tokamak when changing ion species between hydrogen and deuterium. For this purpose, both experimental turbulence measurements and modeling are employed. Local measurements of ion-scale (with wavevector of fluctuations perpendicular to the B-field k ⊥ < 2 cm−1, k ⊥ ρ s < 0.2, where ρs is the ion sound Larmor radius using the deuterium ion mass) electron temperature fluctuations have been performed in the outer core (normalized toroidal flux ρ Tor = 0.65 − 0.8) using a multi-channel correlation electron cyclotron emission diagnostic. Lower root mean square perpendicular fluctuation amplitudes and radial correlation lengths have been measured in hydrogen vs deuterium. Measurements of the cross-phase angle between a normal-incidence reflectometer and an ECE signal were made to infer the cross-phase angle between density and temperature fluctuations. The magnitude of the cross-phase angle was found larger (more out-of-phase) in hydrogen than in deuterium. TRANSP power balance simulations show a larger ion heat flux in hydrogen where the electron-ion heat exchange term is found to play an important role. These experimental observations were used as the basis of a validation study of both quasilinear gyrofluid trapped gyro-Landau fluid-SAT2 and nonlinear gyrokinetic GENE codes. Linear solvers indicate that, at long wavelengths ( k ⊥ ρ s < 1), energy transport in the deuterium discharge is dominated by a mixed ion-temperature-gradient (ITG) and trapped-electron mode turbulence while in hydrogen transport is exclusively and more strongly driven by ITG turbulence. The Ricci validation metric has been used to quantify the agreement between experiments and simulations taking into account both experimental and simulation uncertainties as well as four different observables across different levels of the primacy hierarchy. [ABSTRACT FROM AUTHOR]

Published
2023
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10. High-heat flux ball-pen probe head in ASDEX-Upgrade

Author

Grenfell, G., Adamek, J., Komm, M., Brida, D., Conway, G. D., Manz, P., Tolias, Panagiotis, Eich, T., Sestak, D., Herrmann, A., Nishizawa, T., Stroth, U., Grenfell, G., Adamek, J., Komm, M., Brida, D., Conway, G. D., Manz, P., Tolias, Panagiotis, Eich, T., Sestak, D., Herrmann, A., Nishizawa, T., and Stroth, U.

Abstract

A new high heat flux ball-pen probe head installed on the midplane manipulator is currently being used in ASDEX-Upgrade (AUG). The probe was designed to withstand high heat fluxes making possible the investigation of the plasma edge under harsh conditions, such as low power H-mode. Composed of seven pins (four Langmuir probes, mounted in two Mach probe pairs, and three ball-pen probes), the new probe head allows us to measure several plasma parameters simultaneously and with high temporal resolution. A novel method to correct the sheath potential dynamically accounting for the total secondary electron emission is introduced together with applications to obtain the electron temperature and plasma potential profiles. The total secondary electron emission yield is obtained from particle in cell simulations in AUG condition and probe realistic impact angle with respect to the magnetic field. Finally, the probe capability to investigate turbulence around the separatrix of AUG is discussed.& nbsp, QC 20220322

Published
2022
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11. Experimental Investigations of the H-mode Access in Mixed Hydrogen-Deuterium Plasmas at ASDEX Upgrade

Author

Plank, U, Putterich, T, Angioni, C, Conway, G, Dux, R, Happel, T, Bonanomi, N, Cavedon, M, Gil, L, Mcdermott, R, Schneider, P, Plank U., Putterich T., Angioni C., Conway G. D., Dux R., Happel T., Bonanomi N., Cavedon M., Gil L., McDermott R. M., Schneider P. A., Plank, U, Putterich, T, Angioni, C, Conway, G, Dux, R, Happel, T, Bonanomi, N, Cavedon, M, Gil, L, Mcdermott, R, Schneider, P, Plank U., Putterich T., Angioni C., Conway G. D., Dux R., Happel T., Bonanomi N., Cavedon M., Gil L., McDermott R. M., and Schneider P. A.

Published
2022

12. Experimental study of the edge radial electric field in different drift configurations and its role in the access to H-mode at ASDEX Upgrade.

Author

Plank, U., Brida, D., Conway, G. D., Happel, T., Hubbard, A. E., Pütterich, T., Angioni, C., Cavedon, M., Dux, R., Eich, T., Fischer, R., and Hennequin, P.

Subjects
ELECTRIC fields, PLASMA confinement, TOROIDAL plasma, PLASMA density, PLASMA boundary layers, POWER density
Abstract

The formation of the equilibrium radial electric field (Er) has been studied experimentally at ASDEX Upgrade (AUG) in L-modes of "favorable" (ion ∇ B -drift toward primary X-point) and "unfavorable" (ion ∇ B -drift away from primary X-point) drift configurations, in view of its impact on H-mode access, which changes with drift configurations. Edge electron and ion kinetic profiles and impurity velocity and mean-field Er profiles across the separatrix are investigated, employing new and improved measurement techniques. The experimental results are compared to local neoclassical theory as well as to a simple 1D scrape-off layer (SOL) model. It is found that in L-modes of matched heating power and plasma density, the upstream SOL Er and the main ion pressure gradient in the plasma edge are the same for either drift configurations, whereas the Er well in the confined plasma is shallower in unfavorable compared to the favorable drift configuration. The contributions of toroidal and poloidal main ion flows to Er, which are inferred from local neoclassical theory and the experiment, cannot account for these observed differences. Furthermore, it is found that in the L-mode, the intrinsic toroidal edge rotation decreases with increasing collisionality and it is co-current in the banana-plateau regime for all different drift configurations at AUG. This gives rise to a possible interaction of parallel Pfirsch–Schlüter flows in the SOL with the confined plasma. Thus, the different H-mode power threshold for the two drift configurations cannot be explained in the same way at AUG as suggested by LaBombard et al. [Phys. Plasmas 12, 056111 (2005)] for Alcator C-Mod. Finally, comparisons of Er profiles in favorable and unfavorable drift configurations at the respective confinement transitions show that also the Er gradients are all different, which indirectly indicates a different type or strength of the characteristic edge turbulence in the two drift configurations. [ABSTRACT FROM AUTHOR]

Published
2023
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15. Nonlinear dynamics of energetic-particle driven geodesic acoustic modes in ASDEX Upgrade

Author

Novikau, I., Biancalani, A., Bottino, A., Lauber, Ph., Poli, E., Manz, P., Conway, G. D., Di Siena, A., Ohana, N., Lanti, E., Villard, L., Team, ASDEX Upgrade, and ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Tokamak, Population, FOS: Physical sciences, Electron, Kinetic energy, 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, law.invention, ASDEX Upgrade, law, Physics::Plasma Physics, 0103 physical sciences, 010306 general physics, education, Physics, education.field_of_study, Plasma, Condensed Matter Physics, simulation, Physics - Plasma Physics, Computational physics, Magnetic field, Plasma Physics (physics.plasm-ph), code, Transport phenomena, explanation
Abstract

Turbulence in tokamaks generates radially sheared zonal flows. Their oscillatory counterparts, geodesic acoustic modes (GAMs), appear due to the action of the magnetic field curvature. The GAMs can be driven unstable by an anisotropic energetic particle (EP) population leading to the formation of global radial structures, called energetic-particle-driven geodesic acoustic modes (EGAMs). The EGAMs can redistribute EP energy to the bulk plasma through collisionless wave-particle interaction. In such a way, the EGAMs might contribute to the plasma heating. Thus, investigation of EGAM properties, especially in the velocity space, is necessary for precise understanding of the transport phenomena in tokamak plasmas. In this work, the nonlinear dynamics of EGAMs without considering the mode interaction with the turbulence is investigated with the help of a Mode-Particle-Resonance (MPR) diagnostic implemented in the global gyrokinetic particle-in-cell code ORB5. An ASDEX Upgrade discharge is chosen as a reference case for this investigation due to its rich EP nonlinear dynamics. An experimentally relevant magnetic field configuration, thermal species profiles, and an EP density profile are taken for EGAM chirping modeling and its comparison with available empirical data. The same magnetic configuration is used to explore energy transfer by the mode from the energetic particles to the thermal plasma including kinetic electron effects. For a given EGAM level, the plasma heating by the mode can be significantly enhanced by varying the EP parameters. Electron dynamics decreases the EGAM saturation amplitude and consequently reduces the plasma heating, even though the mode transfers its energy to thermal ions much more than to electrons.

Published
2020
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16. H-mode power threshold studies in mixed ion species plasmas at ASDEX Upgrade

Author

Plank, U, Putterich, T, Angioni, C, Cavedon, M, Conway, G, Fischer, R, Happel, T, Kappatou, A, Mcdermott, R, Schneider, P, Tardini, G, Weiland, M, Plank U., Putterich T., Angioni C., Cavedon M., Conway G. D., Fischer R., Happel T., Kappatou A., Mcdermott R. M., Schneider P. A., Tardini G., Weiland M., Plank, U, Putterich, T, Angioni, C, Cavedon, M, Conway, G, Fischer, R, Happel, T, Kappatou, A, Mcdermott, R, Schneider, P, Tardini, G, Weiland, M, Plank U., Putterich T., Angioni C., Cavedon M., Conway G. D., Fischer R., Happel T., Kappatou A., Mcdermott R. M., Schneider P. A., Tardini G., and Weiland M.

Abstract

Understanding the dependence of the H-mode power threshold, PLH on the main ion composition is crucial for H-mode operation in ITER. In this work, H-mode power threshold studies conducted at ASDEX Upgrade are presented. These were performed in hydrogen plasmas with helium doping and in mixed hydrogen-deuterium plasmas. PLH stays constant on the level of pure hydrogen in hydrogen plasmas with helium doping up to cHe = 20%. Power balance calculations with the transport code ASTRA show that the edge ion heat flux at the L-H transition is independent of helium concentration and applied auxiliary heating, supporting that a critical edge ion heat flux is needed to enter H-mode. A non-linear dependence of PLH on the relative hydrogen content is found. PLH and the edge ion heat flux are constant at the level of pure deuterium for between 0 and 0.5 and constant on the level of pure hydrogen for between 0.8 and 1.

Published
2020

18. Edge turbulence measurements in L-mode and I-mode at ASDEX Upgrade.

Author

Bielajew, R., Conway, G. D., Griener, M., Happel, T., Höfler, K., Howard, N. T., Hubbard, A. E., McCarthy, W., Molina Cabrera, P. A., Nishizawa, T., Rodriguez-Fernandez, P., Silvagni, D., Vanovac, B., Wendler, D., Yoo, C., and White, A. E.

Subjects
*PLASMA turbulence, *TURBULENCE, *ELECTRON emission, *ELECTRON configuration, *EDGES (Geometry)
Abstract

The I-mode confinement regime is promising for future reactor operation due to high energy confinement without high particle confinement. However, the role of edge turbulence in creating I-mode's beneficial transport properties is still unknown. New measurements of edge turbulence ( ρ pol = 0.9 − 1.0) in L-modes and I-modes at low and high densities at ASDEX Upgrade are presented in this paper. A high radial resolution correlation electron cyclotron emission radiometer measures the broadband turbulence throughout the L-mode and I-mode edge and pedestal. The weakly coherent mode (WCM) is measured in both L-mode and I-mode near the last closed flux surface with Te fluctuation levels of 2.3%–4.2%, with a frequency shift between the two phases related to a deeper Er well in I-mode. An n e T e phase diagnostic captures a change of the WCM n e T e phase between L-mode and I-mode from − 171 ° to − 143 °. The thermal He beam diagnostic measures a WCM wavenumber range of −0.5 to −1.0 cm−1. A low-frequency edge oscillation (LFEO) appears in the I-mode phase of these discharges and displays coupling to the WCM, but the LFEO does not appear in the L-mode phase. Linear gyrokinetic simulations of the outer core and pedestal top turbulence indicate that while the dominant turbulent modes in the outer core are ion directed and electrostatic, the turbulence becomes increasingly electron directed and electromagnetic with increasing radius. Collisionality is not found to impact characteristics of the L-mode and I-mode edge turbulence with respect to the presence of the WCM; however, the quality of global confinement decreases with collisionality. [ABSTRACT FROM AUTHOR]

Published
2022
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19. Dependence of the L–H power threshold on the alignment of external non-axisymmetric magnetic perturbations in ASDEX Upgrade.

Author

Willensdorfer, M., Plank, U., Brida, D., Cavedon, M., Conway, G. D., Ryan, D. A., Suttrop, W., Buchholz, R., Dunne, M., Fischer, R., Griener, M., Hobirk, J., Kasilov, S., Kirk, A., McDermott, R. M., Pütterich, T., Tardini, G., and Yu, Q.

Subjects
FLOW velocity, PLASMA boundary layers, MAGNETIC fields, TOROIDAL plasma
Abstract

Experiments at ASDEX Upgrade have been conducted to study the impact of the alignment of external magnetic perturbations (MPs) with n = 2 toroidal mode symmetry on the power threshold of the transition from L- to H-mode ( P LH ). This is interesting for ITER, since its operation will rely on an MP field configuration that securely suppresses edge localized modes (ELMs) while avoiding an increase in the L–H power threshold. P LH can increase up to ≈ 80 % when the external MP field is aligned to maximize the associated plasma response at the edge. This alignment deviates from the equilibrium field pitch and is similar to the one that is required to suppress ELMs by MPs in H-mode. The relative radial magnetic field perturbation δ B r / B T has to exceed a critical value, roughly 1.7 − 2 × 10 − 4 (at the q = 5 surface), to cause an increase in P LH . This value is above the one that is required to sustain ELM suppression at ASDEX Upgrade. Combining plasma response calculations with a critical value of δ B r / B T captures well the measured dependencies of P LH on the alignment of the applied MP field. The increase in P LH is accompanied by a change in the E × B flow velocity ( v E × B ) profile. The application of MPs in L-mode flattens and reverses the edge v E × B profile when at least δ B r / B T ≈ 1.9 × 10 − 4 is applied. This is the same value above which P LH increases. More heating power is needed to roughly achieve the same shear in the v E × B profile at the transition to H-mode as without MPs but with an v E × B profile that is shifted into the ion diamagnetic direction. [ABSTRACT FROM AUTHOR]

Published
2022
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21. Electron temperature fluctuation measurements in the pedestal of improved confinement regimes at ASDEX Upgrade

Author

Bielajew, R., Conway, G. D., Gil, L., Hubbard, A. E., Molina Cabrera, P. A., Davide Silvagni, Viezzer, E., White, A. E., Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, Department of Energy. United States, EUROfusion Consortium, and ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society

Abstract

US DOE (DE-SC0006419, DE-SC0014264, and DE- SC0017381) EUROfusion Consortium (No. 633053)

Published
2019

22. H-mode Power Threshold Studies at ASDEX Upgrade in Mixed Ion Species Plasmas

Author

Plank U., Putterich T., Angioni C., Cavedon M., Conway G. D., Happel T., Kappatou A., McDermott R. M., Schneider P. A., Weiland M., ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, Plank, U, Putterich, T, Angioni, C, Cavedon, M, Conway, G, Happel, T, Kappatou, A, Mcdermott, R, Schneider, P, and Weiland, M

Subjects
palsma
Published
2019

23. Electron temperature fluctuation measurements in the pedestal of improved confinement regimes at ASDEX Upgrade

Author

Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, Department of Energy. United States, EUROfusion Consortium, Bielajew, R., Conway, G. D., Gil, L., Hubbard, A. E., Molina Cabrera, P. A., Silvagni, D., Viezzer, Eleonora, White, A. E., Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, Department of Energy. United States, EUROfusion Consortium, Bielajew, R., Conway, G. D., Gil, L., Hubbard, A. E., Molina Cabrera, P. A., Silvagni, D., Viezzer, Eleonora, and White, A. E.

Published
2019

24. Stationary ELM-free H-mode in ASDEX Upgrade

Author

Gil, L, Silva, C, Happel, T, Birkenmeier, G, Cavedon, M, Conway, G, Guimarais, L, Putterich, T, Santos, J, Schubert, M, Seliunin, E, Silva, A, Stober, J, Stroth, U, Trier, E, Wolfrum, E, Gil L., Silva C., Happel T., Birkenmeier G., Cavedon M., Conway G. D., Guimarais L., Putterich T., Santos J., Schubert M., Seliunin E., Silva A., Stober J., Stroth U., Trier E., Wolfrum E., Gil, L, Silva, C, Happel, T, Birkenmeier, G, Cavedon, M, Conway, G, Guimarais, L, Putterich, T, Santos, J, Schubert, M, Seliunin, E, Silva, A, Stober, J, Stroth, U, Trier, E, Wolfrum, E, Gil L., Silva C., Happel T., Birkenmeier G., Cavedon M., Conway G. D., Guimarais L., Putterich T., Santos J., Schubert M., Seliunin E., Silva A., Stober J., Stroth U., Trier E., and Wolfrum E.

Published
2019

25. H-mode power threshold studies at ASDEX upgrade in mixed ion species plasmas

Author

Plank, U, Putterich, T, Angioni, C, Cavedon, M, Conway, G, Happel, T, Kappatou, A, Mcdermott, R, Schneider, P, Weiland, M, Plank U., Putterich T., Angioni C., Cavedon M., Conway G. D., Happel T., Kappatou A., McDermott R. M., Schneider P. A., Weiland M., Plank, U, Putterich, T, Angioni, C, Cavedon, M, Conway, G, Happel, T, Kappatou, A, Mcdermott, R, Schneider, P, Weiland, M, Plank U., Putterich T., Angioni C., Cavedon M., Conway G. D., Happel T., Kappatou A., McDermott R. M., Schneider P. A., and Weiland M.

Published
2019

26. Link between divertor conditions and high-field-side/low-field-side midplane density profiles in H-mode plasmas at ASDEX Upgrade

Author

Guimarais, L, Silva, C, Bernert, M, Brida, D, Cavedon, M, Conway, G, Drenik, A, Gil, L, Reichbauer, T, Reimold, F, Santos, J, Seliunin, E, Silva, A, Stroth, U, Vicente, J, Wolfrum, E, Guimarais L., Silva C., Bernert M., Brida D., Cavedon M., Conway G. D., Drenik A., Gil L., Reichbauer T., Reimold F., Santos J., Seliunin E., Silva A., Stroth U., Vicente J., Wolfrum E., Guimarais, L, Silva, C, Bernert, M, Brida, D, Cavedon, M, Conway, G, Drenik, A, Gil, L, Reichbauer, T, Reimold, F, Santos, J, Seliunin, E, Silva, A, Stroth, U, Vicente, J, Wolfrum, E, Guimarais L., Silva C., Bernert M., Brida D., Cavedon M., Conway G. D., Drenik A., Gil L., Reichbauer T., Reimold F., Santos J., Seliunin E., Silva A., Stroth U., Vicente J., and Wolfrum E.

Abstract

The connection between midplane and divertor conditions is studied on ASDEX Upgrade (AUG) for H-mode scenarios. H-mode discharges with variations in fuelling, heating power and impurity seeding are analysed, enabling to disentangle their impact on the evolution of midplane density profiles. The O-mode reflectometer installed on AUG provides unique insights on the midplane density profiles thanks to the ability to measure simultaneously at the high-field-side (HFS) and the low-field-side (LFS). At the inner divertor, with the onset of detachment, a region of high density is formed (HFS high density front, HFSHD) that expands into the HFS midplane, leading to strong poloidal asymmetries in the main chamber scrape-off layer (SOL) density. A good agreement is observed between the evolution of the density profiles at the midplane and that of the divertor volume density confirming the strong influence of divertor conditions on the midplane density profiles at the HFS. Our results confirm the existence of a relationship between plasma confinement, the shift in the midplane LFS density profile and the presence of the HFSHD with respect to changes in seeding and fuelling. It is established that the separatrix density at the LFS is better correlated with the neutral pressure at the outer target while the HFS SOL density follows the neutral pressure at the inner divertor. A comprehensive characterisation of the edge-localised mode (ELM) evolution at the midplane and divertor is performed demonstrating that also during the ELM cycle the divertor conditions have a strong effect on the SOL density at the midplane. The most striking result is the observation of a HFSHD at the HFS midplane just after the ELM crash associated with strong inner divertor detachment.

Published
2019

27. Overview of physics studies on ASDEX Upgrade

Author

Meyer, H, Angioni, C, Albert, C, Arden, N, Arredondo Parra, R, Asunta, O, De Baar, M, Balden, M, Bandaru, V, Behler, K, Bergmann, A, Bernardo, J, Bernert, M, Biancalani, A, Bilato, R, Birkenmeier, G, Blanken, T, Bobkov, V, Bock, A, Bolzonella, T, Bortolon, A, Boswirth, B, Bottereau, C, Bottino, A, Van Den Brand, H, Brezinsek, S, Brida, D, Brochard, F, Bruhn, C, Buchanan, J, Buhler, A, Burckhart, A, Camenen, Y, Carlton, D, Carr, M, Carralero, D, Castaldo, C, Cavedon, M, Cazzaniga, C, Ceccuzzi, S, Challis, C, Chankin, A, Chapman, S, Cianfarani, C, Clairet, F, Coda, S, Coelho, R, Coenen, J, Colas, L, Conway, G, Costea, S, Coster, D, Cote, T, Creely, A, Croci, G, Cseh, G, Czarnecka, A, Cziegler, I, D'Arcangelo, O, David, P, Day, C, Delogu, R, De Marne, P, Denk, S, Denner, P, Dibon, M, Di Siena, A, Douai, D, Drenik, A, Drube, R, Dunne, M, Duval, B, Dux, R, Eich, T, Elgeti, S, Engelhardt, K, Erdos, B, Erofeev, I, Esposito, B, Fable, E, Faitsch, M, Fantz, U, Faugel, H, Faust, I, Felici, F, Ferreira, J, Fietz, S, Figuereido, A, Fischer, R, Ford, O, Frassinetti, L, Freethy, S, Froschle, M, Fuchert, G, Fuchs, J, Funfgelder, H, Galazka, K, Galdon-Quiroga, J, Gallo, A, Gao, Y, Garavaglia, S, Garcia-Carrasco, A, Garcia-Munoz, M, Geiger, B, Giannone, L, Gil, L, Giovannozzi, E, Gleason-Gonzalez, C, Gloggler, S, Gobbin, M, Gorler, T, Gomez Ortiz, I, Gonzalez Martin, J, Goodman, T, Gorini, G, Gradic, D, Grater, A, Granucci, G, Greuner, H, Griener, M, Groth, M, Gude, A, Gunter, S, Guimarais, L, Haas, G, Hakola, A, Ham, C, Happel, T, Den Harder, N, Harrer, G, Harrison, J, Hauer, V, Hayward-Schneider, T, Hegna, C, Heinemann, B, Heinzel, S, Hellsten, T, Henderson, S, Hennequin, P, Herrmann, A, Heyn, M, Heyn, E, Hitzler, F, Hobirk, J, Hofler, K, Holzl, M, Hoschen, T, Holm, J, Hopf, C, Hornsby, W, Horvath, L, Houben, A, Huber, A, Igochine, V, Ilkei, T, Ivanova-Stanik, I, Jacob, W, Jacobsen, A, Janky, F, Jansen Van Vuuren, A, Jardin, A, Jaulmes, F, Jenko, F, Jensen, T, Joffrin, E, Kasemann, C, Kallenbach, A, Kalvin, S, Kantor, M, Kappatou, A, Kardaun, O, Karhunen, J, Kasilov, S, Kazakov, Y, Kernbichler, W, Kirk, A, Kjer Hansen, S, Klevarova, V, Kocsis, G, Kohn, A, Koubiti, M, Krieger, K, Krivska, A, Kramer-Flecken, A, Kudlacek, O, Kurki-Suonio, T, Kurzan, B, Labit, B, Lackner, K, Laggner, F, Lang, P, Lauber, P, Lebschy, A, Leuthold, N, Li, M, Linder, O, Lipschultz, B, Liu, F, Liu, Y, Lohs, A, Lu, Z, Luda Di Cortemiglia, T, Luhmann, N, Lunsford, R, Lunt, T, Lyssoivan, A, Maceina, T, Madsen, J, Maggiora, R, Maier, H, Maj, O, Mailloux, J, Maingi, R, Maljaars, E, Manas, P, Mancini, A, Manhard, A, Manso, M, Mantica, P, Mantsinen, M, Manz, P, Maraschek, M, Martens, C, Martin, P, Marrelli, L, Martitsch, A, Mayer, M, Mazon, D, Mccarthy, P, Mcdermott, R, Meister, H, Medvedeva, A, Merkel, R, Merle, A, Mertens, V, Meshcheriakov, D, Meyer, O, Miettunen, J, Milanesio, D, Mink, F, Mlynek, A, Monaco, F, Moon, C, Nabais, F, Nemes-Czopf, A, Neu, G, Neu, R, Nielsen, A, Nielsen, S, Nikolaeva, V, Nocente, M, Noterdaeme, J, Novikau, I, Nowak, S, Oberkofler, M, Oberparleiter, M, Ochoukov, R, Odstrcil, T, Olsen, J, Orain, F, Palermo, F, Pan, O, Papp, G, Paradela Perez, I, Pau, A, Pautasso, G, Penzel, F, Petersson, P, Pinzon Acosta, J, Piovesan, P, Piron, C, Pitts, R, Plank, U, Plaum, B, Ploeckl, B, Plyusnin, V, Pokol, G, Poli, E, Porte, L, Potzel, S, Prisiazhniuk, D, Putterich, T, Ramisch, M, Rasmussen, J, Ratta, G, Ratynskaia, S, Raupp, G, Ravera, G, Refy, D, Reich, M, Reimold, F, Reiser, D, Ribeiro, T, Riesch, J, Riedl, R, Rittich, D, Rivero-Rodriguez, J, Rocchi, G, Rodriguez-Ramos, M, Rohde, V, Ross, A, Rott, M, Rubel, M, Ryan, D, Ryter, F, Saarelma, S, Salewski, M, Salmi, A, Sanchis-Sanchez, L, Santos, J, Sauter, O, Scarabosio, A, Schall, G, Schmid, K, Schmitz, O, Schneider, P, Schrittwieser, R, Schubert, M, Schwarz-Selinger, T, Schweinzer, J, Scott, B, Sehmer, T, Seliunin, E, Sertoli, M, Shabbir, A, Shalpegin, A, Shao, L, Sharapov, S, Sias, G, Siccinio, M, Sieglin, B, Sigalov, A, Silva, A, Silva, C, Silvagni, D, Simon, P, Simpson, J, Smigelskis, E, Snicker, A, Sommariva, C, Sozzi, C, Spolaore, M, Stegmeir, A, Stejner, M, Stober, J, Stroth, U, Strumberger, E, Suarez, G, Sun, H, Suttrop, W, Sytova, E, Szepesi, T, Tal, B, Tala, T, Tardini, G, Tardocchi, M, Teschke, M, Terranova, D, Tierens, W, Thoren, E, Told, D, Tolias, P, Tudisco, O, Treutterer, W, Trier, E, Tripsky, M, Valisa, M, Valovic, M, Vanovac, B, Van Vugt, D, Varoutis, S, Verdoolaege, G, Vianello, N, Vicente, J, Vierle, T, Viezzer, E, Von Toussaint, U, Wagner, D, Wang, N, Wang, X, Weiland, M, White, A, Wiesen, S, Willensdorfer, M, Wiringer, B, Wischmeier, M, Wolf, R, Wolfrum, E, Xiang, L, Yang, Q, Yang, Z, Yu, Q, Zagorski, R, Zammuto, I, Zhang, W, Van Zeeland, M, Zehetbauer, T, Zilker, M, Zoletnik, S, Zohm, H, Meyer H., Angioni C., Albert C. G., Arden N., Arredondo Parra R., Asunta O., De Baar M., Balden M., Bandaru V., Behler K., Bergmann A., Bernardo J., Bernert M., Biancalani A., Bilato R., Birkenmeier G., Blanken T. C., Bobkov V., Bock A., Bolzonella T., Bortolon A., Boswirth B., Bottereau C., Bottino A., Van Den Brand H., Brezinsek S., Brida D., Brochard F., Bruhn C., Buchanan J., Buhler A., Burckhart A., Camenen Y., Carlton D., Carr M., Carralero D., Castaldo C., Cavedon M., Cazzaniga C., Ceccuzzi S., Challis C., Chankin A., Chapman S., Cianfarani C., Clairet F., Coda S., Coelho R., Coenen J. W., Colas L., Conway G. D., Costea S., Coster D. P., Cote T. B., Creely A., Croci G., Cseh G., Czarnecka A., Cziegler I., D'Arcangelo O., David P., Day C., Delogu R., De Marne P., Denk S. S., Denner P., Dibon M., Di Siena A., Douai D., Drenik A., Drube R., Dunne M., Duval B. P., Dux R., Eich T., Elgeti S., Engelhardt K., Erdos B., Erofeev I., Esposito B., Fable E., Faitsch M., Fantz U., Faugel H., Faust I., Felici F., Ferreira J., Fietz S., Figuereido A., Fischer R., Ford O., Frassinetti L., Freethy S., Froschle M., Fuchert G., Fuchs J. C., Funfgelder H., Galazka K., Galdon-Quiroga J., Gallo A., Gao Y., Garavaglia S., Garcia-Carrasco A., Garcia-Munoz M., Geiger B., Giannone L., Gil L., Giovannozzi E., Gleason-Gonzalez C., Gloggler S., Gobbin M., Gorler T., Gomez Ortiz I., Gonzalez Martin J., Goodman T., Gorini G., Gradic D., Grater A., Granucci G., Greuner H., Griener M., Groth M., Gude A., Gunter S., Guimarais L., Haas G., Hakola A. H., Ham C., Happel T., Den Harder N., Harrer G. F., Harrison J., Hauer V., Hayward-Schneider T., Hegna C. C., Heinemann B., Heinzel S., Hellsten T., Henderson S., Hennequin P., Herrmann A., Heyn M. F., Heyn E., Hitzler F., Hobirk J., Hofler K., Holzl M., Hoschen T., Holm J. H., Hopf C., Hornsby W. A., Horvath L., Houben A., Huber A., Igochine V., Ilkei T., Ivanova-Stanik I., Jacob W., Jacobsen A. S., Janky F., Jansen Van Vuuren A., Jardin A., Jaulmes F., Jenko F., Jensen T., Joffrin E., Kasemann C. -P., Kallenbach A., Kalvin S., Kantor M., Kappatou A., Kardaun O., Karhunen J., Kasilov S., Kazakov Y., Kernbichler W., Kirk A., Kjer Hansen S., Klevarova V., Kocsis G., Kohn A., Koubiti M., Krieger K., Krivska A., Kramer-Flecken A., Kudlacek O., Kurki-Suonio T., Kurzan B., Labit B., Lackner K., Laggner F., Lang P. T., Lauber P., Lebschy A., Leuthold N., Li M., Linder O., Lipschultz B., Liu F., Liu Y., Lohs A., Lu Z., Luda Di Cortemiglia T., Luhmann N. C., Lunsford R., Lunt T., Lyssoivan A., Maceina T., Madsen J., Maggiora R., Maier H., Maj O., Mailloux J., Maingi R., Maljaars E., Manas P., Mancini A., Manhard A., Manso M. -E., Mantica P., Mantsinen M., Manz P., Maraschek M., Martens C., Martin P., Marrelli L., Martitsch A., Mayer M., Mazon D., McCarthy P. J., McDermott R., Meister H., Medvedeva A., Merkel R., Merle A., Mertens V., Meshcheriakov D., Meyer O., Miettunen J., Milanesio D., Mink F., Mlynek A., Monaco F., Moon C., Nabais F., Nemes-Czopf A., Neu G., Neu R., Nielsen A. H., Nielsen S. K., Nikolaeva V., Nocente M., Noterdaeme J. -M., Novikau I., Nowak S., Oberkofler M., Oberparleiter M., Ochoukov R., Odstrcil T., Olsen J., Orain F., Palermo F., Pan O., Papp G., Paradela Perez I., Pau A., Pautasso G., Penzel F., Petersson P., Pinzon Acosta J., Piovesan P., Piron C., Pitts R., Plank U., Plaum B., Ploeckl B., Plyusnin V., Pokol G., Poli E., Porte L., Potzel S., Prisiazhniuk D., Putterich T., Ramisch M., Rasmussen J., Ratta G. A., Ratynskaia S., Raupp G., Ravera G. L., Refy D., Reich M., Reimold F., Reiser D., Ribeiro T., Riesch J., Riedl R., Rittich D., Rivero-Rodriguez J. F., Rocchi G., Rodriguez-Ramos M., Rohde V., Ross A., Rott M., Rubel M., Ryan D., Ryter F., Saarelma S., Salewski M., Salmi A., Sanchis-Sanchez L., Santos J., Sauter O., Scarabosio A., Schall G., Schmid K., Schmitz O., Schneider P. A., Schrittwieser R., Schubert M., Schwarz-Selinger T., Schweinzer J., Scott B., Sehmer T., Seliunin E., Sertoli M., Shabbir A., Shalpegin A., Shao L., Sharapov S., Sias G., Siccinio M., Sieglin B., Sigalov A., Silva A., Silva C., Silvagni D., Simon P., Simpson J., Smigelskis E., Snicker A., Sommariva C., Sozzi C., Spolaore M., Stegmeir A., Stejner M., Stober J., Stroth U., Strumberger E., Suarez G., Sun H. -J., Suttrop W., Sytova E., Szepesi T., Tal B., Tala T., Tardini G., Tardocchi M., Teschke M., Terranova D., Tierens W., Thoren E., Told D., Tolias P., Tudisco O., Treutterer W., Trier E., Tripsky M., Valisa M., Valovic M., Vanovac B., Van Vugt D., Varoutis S., Verdoolaege G., Vianello N., Vicente J., Vierle T., Viezzer E., Von Toussaint U., Wagner D., Wang N., Wang X., Weiland M., White A. E., Wiesen S., Willensdorfer M., Wiringer B., Wischmeier M., Wolf R., Wolfrum E., Xiang L., Yang Q., Yang Z., Yu Q., Zagorski R., Zammuto I., Zhang W., Van Zeeland M., Zehetbauer T., Zilker M., Zoletnik S., Zohm H., Meyer, H, Angioni, C, Albert, C, Arden, N, Arredondo Parra, R, Asunta, O, De Baar, M, Balden, M, Bandaru, V, Behler, K, Bergmann, A, Bernardo, J, Bernert, M, Biancalani, A, Bilato, R, Birkenmeier, G, Blanken, T, Bobkov, V, Bock, A, Bolzonella, T, Bortolon, A, Boswirth, B, Bottereau, C, Bottino, A, Van Den Brand, H, Brezinsek, S, Brida, D, Brochard, F, Bruhn, C, Buchanan, J, Buhler, A, Burckhart, A, Camenen, Y, Carlton, D, Carr, M, Carralero, D, Castaldo, C, Cavedon, M, Cazzaniga, C, Ceccuzzi, S, Challis, C, Chankin, A, Chapman, S, Cianfarani, C, Clairet, F, Coda, S, Coelho, R, Coenen, J, Colas, L, Conway, G, Costea, S, Coster, D, Cote, T, Creely, A, Croci, G, Cseh, G, Czarnecka, A, Cziegler, I, D'Arcangelo, O, David, P, Day, C, Delogu, R, De Marne, P, Denk, S, Denner, P, Dibon, M, Di Siena, A, Douai, D, Drenik, A, Drube, R, Dunne, M, Duval, B, Dux, R, Eich, T, Elgeti, S, Engelhardt, K, Erdos, B, Erofeev, I, Esposito, B, Fable, E, Faitsch, M, Fantz, U, Faugel, H, Faust, I, Felici, F, Ferreira, J, Fietz, S, Figuereido, A, Fischer, R, Ford, O, Frassinetti, L, Freethy, S, Froschle, M, Fuchert, G, Fuchs, J, Funfgelder, H, Galazka, K, Galdon-Quiroga, J, Gallo, A, Gao, Y, Garavaglia, S, Garcia-Carrasco, A, Garcia-Munoz, M, Geiger, B, Giannone, L, Gil, L, Giovannozzi, E, Gleason-Gonzalez, C, Gloggler, S, Gobbin, M, Gorler, T, Gomez Ortiz, I, Gonzalez Martin, J, Goodman, T, Gorini, G, Gradic, D, Grater, A, Granucci, G, Greuner, H, Griener, M, Groth, M, Gude, A, Gunter, S, Guimarais, L, Haas, G, Hakola, A, Ham, C, Happel, T, Den Harder, N, Harrer, G, Harrison, J, Hauer, V, Hayward-Schneider, T, Hegna, C, Heinemann, B, Heinzel, S, Hellsten, T, Henderson, S, Hennequin, P, Herrmann, A, Heyn, M, Heyn, E, Hitzler, F, Hobirk, J, Hofler, K, Holzl, M, Hoschen, T, Holm, J, Hopf, C, Hornsby, W, Horvath, L, Houben, A, Huber, A, Igochine, V, Ilkei, T, Ivanova-Stanik, I, Jacob, W, Jacobsen, A, Janky, F, Jansen Van Vuuren, A, Jardin, A, Jaulmes, F, Jenko, F, Jensen, T, Joffrin, E, Kasemann, C, Kallenbach, A, Kalvin, S, Kantor, M, Kappatou, A, Kardaun, O, Karhunen, J, Kasilov, S, Kazakov, Y, Kernbichler, W, Kirk, A, Kjer Hansen, S, Klevarova, V, Kocsis, G, Kohn, A, Koubiti, M, Krieger, K, Krivska, A, Kramer-Flecken, A, Kudlacek, O, Kurki-Suonio, T, Kurzan, B, Labit, B, Lackner, K, Laggner, F, Lang, P, Lauber, P, Lebschy, A, Leuthold, N, Li, M, Linder, O, Lipschultz, B, Liu, F, Liu, Y, Lohs, A, Lu, Z, Luda Di Cortemiglia, T, Luhmann, N, Lunsford, R, Lunt, T, Lyssoivan, A, Maceina, T, Madsen, J, Maggiora, R, Maier, H, Maj, O, Mailloux, J, Maingi, R, Maljaars, E, Manas, P, Mancini, A, Manhard, A, Manso, M, Mantica, P, Mantsinen, M, Manz, P, Maraschek, M, Martens, C, Martin, P, Marrelli, L, Martitsch, A, Mayer, M, Mazon, D, Mccarthy, P, Mcdermott, R, Meister, H, Medvedeva, A, Merkel, R, Merle, A, Mertens, V, Meshcheriakov, D, Meyer, O, Miettunen, J, Milanesio, D, Mink, F, Mlynek, A, Monaco, F, Moon, C, Nabais, F, Nemes-Czopf, A, Neu, G, Neu, R, Nielsen, A, Nielsen, S, Nikolaeva, V, Nocente, M, Noterdaeme, J, Novikau, I, Nowak, S, Oberkofler, M, Oberparleiter, M, Ochoukov, R, Odstrcil, T, Olsen, J, Orain, F, Palermo, F, Pan, O, Papp, G, Paradela Perez, I, Pau, A, Pautasso, G, Penzel, F, Petersson, P, Pinzon Acosta, J, Piovesan, P, Piron, C, Pitts, R, Plank, U, Plaum, B, Ploeckl, B, Plyusnin, V, Pokol, G, Poli, E, Porte, L, Potzel, S, Prisiazhniuk, D, Putterich, T, Ramisch, M, Rasmussen, J, Ratta, G, Ratynskaia, S, Raupp, G, Ravera, G, Refy, D, Reich, M, Reimold, F, Reiser, D, Ribeiro, T, Riesch, J, Riedl, R, Rittich, D, Rivero-Rodriguez, J, Rocchi, G, Rodriguez-Ramos, M, Rohde, V, Ross, A, Rott, M, Rubel, M, Ryan, D, Ryter, F, Saarelma, S, Salewski, M, Salmi, A, Sanchis-Sanchez, L, Santos, J, Sauter, O, Scarabosio, A, Schall, G, Schmid, K, Schmitz, O, Schneider, P, Schrittwieser, R, Schubert, M, Schwarz-Selinger, T, Schweinzer, J, Scott, B, Sehmer, T, Seliunin, E, Sertoli, M, Shabbir, A, Shalpegin, A, Shao, L, Sharapov, S, Sias, G, Siccinio, M, Sieglin, B, Sigalov, A, Silva, A, Silva, C, Silvagni, D, Simon, P, Simpson, J, Smigelskis, E, Snicker, A, Sommariva, C, Sozzi, C, Spolaore, M, Stegmeir, A, Stejner, M, Stober, J, Stroth, U, Strumberger, E, Suarez, G, Sun, H, Suttrop, W, Sytova, E, Szepesi, T, Tal, B, Tala, T, Tardini, G, Tardocchi, M, Teschke, M, Terranova, D, Tierens, W, Thoren, E, Told, D, Tolias, P, Tudisco, O, Treutterer, W, Trier, E, Tripsky, M, Valisa, M, Valovic, M, Vanovac, B, Van Vugt, D, Varoutis, S, Verdoolaege, G, Vianello, N, Vicente, J, Vierle, T, Viezzer, E, Von Toussaint, U, Wagner, D, Wang, N, Wang, X, Weiland, M, White, A, Wiesen, S, Willensdorfer, M, Wiringer, B, Wischmeier, M, Wolf, R, Wolfrum, E, Xiang, L, Yang, Q, Yang, Z, Yu, Q, Zagorski, R, Zammuto, I, Zhang, W, Van Zeeland, M, Zehetbauer, T, Zilker, M, Zoletnik, S, Zohm, H, Meyer H., Angioni C., Albert C. G., Arden N., Arredondo Parra R., Asunta O., De Baar M., Balden M., Bandaru V., Behler K., Bergmann A., Bernardo J., Bernert M., Biancalani A., Bilato R., Birkenmeier G., Blanken T. C., Bobkov V., Bock A., Bolzonella T., Bortolon A., Boswirth B., Bottereau C., Bottino A., Van Den Brand H., Brezinsek S., Brida D., Brochard F., Bruhn C., Buchanan J., Buhler A., Burckhart A., Camenen Y., Carlton D., Carr M., Carralero D., Castaldo C., Cavedon M., Cazzaniga C., Ceccuzzi S., Challis C., Chankin A., Chapman S., Cianfarani C., Clairet F., Coda S., Coelho R., Coenen J. W., Colas L., Conway G. D., Costea S., Coster D. P., Cote T. B., Creely A., Croci G., Cseh G., Czarnecka A., Cziegler I., D'Arcangelo O., David P., Day C., Delogu R., De Marne P., Denk S. S., Denner P., Dibon M., Di Siena A., Douai D., Drenik A., Drube R., Dunne M., Duval B. P., Dux R., Eich T., Elgeti S., Engelhardt K., Erdos B., Erofeev I., Esposito B., Fable E., Faitsch M., Fantz U., Faugel H., Faust I., Felici F., Ferreira J., Fietz S., Figuereido A., Fischer R., Ford O., Frassinetti L., Freethy S., Froschle M., Fuchert G., Fuchs J. C., Funfgelder H., Galazka K., Galdon-Quiroga J., Gallo A., Gao Y., Garavaglia S., Garcia-Carrasco A., Garcia-Munoz M., Geiger B., Giannone L., Gil L., Giovannozzi E., Gleason-Gonzalez C., Gloggler S., Gobbin M., Gorler T., Gomez Ortiz I., Gonzalez Martin J., Goodman T., Gorini G., Gradic D., Grater A., Granucci G., Greuner H., Griener M., Groth M., Gude A., Gunter S., Guimarais L., Haas G., Hakola A. H., Ham C., Happel T., Den Harder N., Harrer G. F., Harrison J., Hauer V., Hayward-Schneider T., Hegna C. C., Heinemann B., Heinzel S., Hellsten T., Henderson S., Hennequin P., Herrmann A., Heyn M. F., Heyn E., Hitzler F., Hobirk J., Hofler K., Holzl M., Hoschen T., Holm J. H., Hopf C., Hornsby W. A., Horvath L., Houben A., Huber A., Igochine V., Ilkei T., Ivanova-Stanik I., Jacob W., Jacobsen A. S., Janky F., Jansen Van Vuuren A., Jardin A., Jaulmes F., Jenko F., Jensen T., Joffrin E., Kasemann C. -P., Kallenbach A., Kalvin S., Kantor M., Kappatou A., Kardaun O., Karhunen J., Kasilov S., Kazakov Y., Kernbichler W., Kirk A., Kjer Hansen S., Klevarova V., Kocsis G., Kohn A., Koubiti M., Krieger K., Krivska A., Kramer-Flecken A., Kudlacek O., Kurki-Suonio T., Kurzan B., Labit B., Lackner K., Laggner F., Lang P. T., Lauber P., Lebschy A., Leuthold N., Li M., Linder O., Lipschultz B., Liu F., Liu Y., Lohs A., Lu Z., Luda Di Cortemiglia T., Luhmann N. C., Lunsford R., Lunt T., Lyssoivan A., Maceina T., Madsen J., Maggiora R., Maier H., Maj O., Mailloux J., Maingi R., Maljaars E., Manas P., Mancini A., Manhard A., Manso M. -E., Mantica P., Mantsinen M., Manz P., Maraschek M., Martens C., Martin P., Marrelli L., Martitsch A., Mayer M., Mazon D., McCarthy P. J., McDermott R., Meister H., Medvedeva A., Merkel R., Merle A., Mertens V., Meshcheriakov D., Meyer O., Miettunen J., Milanesio D., Mink F., Mlynek A., Monaco F., Moon C., Nabais F., Nemes-Czopf A., Neu G., Neu R., Nielsen A. H., Nielsen S. K., Nikolaeva V., Nocente M., Noterdaeme J. -M., Novikau I., Nowak S., Oberkofler M., Oberparleiter M., Ochoukov R., Odstrcil T., Olsen J., Orain F., Palermo F., Pan O., Papp G., Paradela Perez I., Pau A., Pautasso G., Penzel F., Petersson P., Pinzon Acosta J., Piovesan P., Piron C., Pitts R., Plank U., Plaum B., Ploeckl B., Plyusnin V., Pokol G., Poli E., Porte L., Potzel S., Prisiazhniuk D., Putterich T., Ramisch M., Rasmussen J., Ratta G. A., Ratynskaia S., Raupp G., Ravera G. L., Refy D., Reich M., Reimold F., Reiser D., Ribeiro T., Riesch J., Riedl R., Rittich D., Rivero-Rodriguez J. F., Rocchi G., Rodriguez-Ramos M., Rohde V., Ross A., Rott M., Rubel M., Ryan D., Ryter F., Saarelma S., Salewski M., Salmi A., Sanchis-Sanchez L., Santos J., Sauter O., Scarabosio A., Schall G., Schmid K., Schmitz O., Schneider P. A., Schrittwieser R., Schubert M., Schwarz-Selinger T., Schweinzer J., Scott B., Sehmer T., Seliunin E., Sertoli M., Shabbir A., Shalpegin A., Shao L., Sharapov S., Sias G., Siccinio M., Sieglin B., Sigalov A., Silva A., Silva C., Silvagni D., Simon P., Simpson J., Smigelskis E., Snicker A., Sommariva C., Sozzi C., Spolaore M., Stegmeir A., Stejner M., Stober J., Stroth U., Strumberger E., Suarez G., Sun H. -J., Suttrop W., Sytova E., Szepesi T., Tal B., Tala T., Tardini G., Tardocchi M., Teschke M., Terranova D., Tierens W., Thoren E., Told D., Tolias P., Tudisco O., Treutterer W., Trier E., Tripsky M., Valisa M., Valovic M., Vanovac B., Van Vugt D., Varoutis S., Verdoolaege G., Vianello N., Vicente J., Vierle T., Viezzer E., Von Toussaint U., Wagner D., Wang N., Wang X., Weiland M., White A. E., Wiesen S., Willensdorfer M., Wiringer B., Wischmeier M., Wolf R., Wolfrum E., Xiang L., Yang Q., Yang Z., Yu Q., Zagorski R., Zammuto I., Zhang W., Van Zeeland M., Zehetbauer T., Zilker M., Zoletnik S., and Zohm H.

Abstract

The ASDEX Upgrade (AUG) programme, jointly run with the EUROfusion MST1 task force, continues to significantly enhance the physics base of ITER and DEMO. Here, the full tungsten wall is a key asset for extrapolating to future devices. The high overall heating power, flexible heating mix and comprehensive diagnostic set allows studies ranging from mimicking the scrape-off-layer and divertor conditions of ITER and DEMO at high density to fully non-inductive operation (q 95 = 5.5, ) at low density. Higher installed electron cyclotron resonance heating power 6 MW, new diagnostics and improved analysis techniques have further enhanced the capabilities of AUG. Stable high-density H-modes with MW m-1 with fully detached strike-points have been demonstrated. The ballooning instability close to the separatrix has been identified as a potential cause leading to the H-mode density limit and is also found to play an important role for the access to small edge-localized modes (ELMs). Density limit disruptions have been successfully avoided using a path-oriented approach to disruption handling and progress has been made in understanding the dissipation and avoidance of runaway electron beams. ELM suppression with resonant magnetic perturbations is now routinely achieved reaching transiently . This gives new insight into the field penetration physics, in particular with respect to plasma flows. Modelling agrees well with plasma response measurements and a helically localised ballooning structure observed prior to the ELM is evidence for the changed edge stability due to the magnetic perturbations. The impact of 3D perturbations on heat load patterns and fast-ion losses have been further elaborated. Progress has also been made in understanding the ELM cycle itself. Here, new fast measurements of and E r allow for inter ELM transport analysis confirming that E r is dominated by the diamagnetic term even for fast timescales. New analysis techniques allow detailed comparison of the EL

Published
2019

28. Plasma turbulence structure in the ASDEX Upgrade tokamak, Overview

Author

Hennequin, Pascale, Happel, T., Pinzón, J R, Freethy, Simon, Görler, T., Conway, G. D., Angioni, C., Trier, Elisée, Schneider, P., Stroth, U., ASDEX Upgrade Team, The, EUROfusion MST1 Team, The, Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Max-Planck-Institut für Plasmaphysik [Garching] (IPP), and Physik-Department E28, Technishe Universität München, Garching

Subjects
[PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018

29. Turbulence measurements and gyrokinetic validation at ASDEX Upgrade

Author

Freethy, Simon, Görler, T., Creely, A. J., Conway, G. D., Denk, S., Happel, T., Hennequin, Pascale, White, A. E., ASDEX Upgrade Team, The, Max-Planck-Institut für Plasmaphysik [Garching] (IPP), Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)

Subjects
[PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018

30. Studying ELM filaments with Doppler reflectometry in ASDEX Upgrade

Author

Trier, Elisée, Hennequin, Pascale, Pinzón, J R, Hoelzl, M., Conway, G. D., Happel, T., Harrer, G., Mink, F., Orain, F., Wolfrum, E., Asdex Upgrade Team, The, Mst1 Eurofusion Team, The, Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Max-Planck-Institut für Plasmaphysik [Garching] (IPP), Max Planck Institute for Plasma physics (IPP-MPG), Max-Planck-Gesellschaft, and PIBERNE, Rodrigue

Subjects
[PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018

31. Measurement of the complete core plasma flow across the LOC-SOC transition at ASDEX Upgrade

Author

Lebschy, A, Mcdermott, R, Angioni, C, Geiger, B, Prisiazhniuk, D, Cavedon, M, Conway, G, Dux, R, Dunne, M, Kappatou, A, Putterich, T, Stroth, U, Viezzer, E, Lebschy A., McDermott R. M., Angioni C., Geiger B., Prisiazhniuk D., Cavedon M., Conway G. D., Dux R., Dunne M. G., Kappatou A., Putterich T., Stroth U., Viezzer E., Lebschy, A, Mcdermott, R, Angioni, C, Geiger, B, Prisiazhniuk, D, Cavedon, M, Conway, G, Dux, R, Dunne, M, Kappatou, A, Putterich, T, Stroth, U, Viezzer, E, Lebschy A., McDermott R. M., Angioni C., Geiger B., Prisiazhniuk D., Cavedon M., Conway G. D., Dux R., Dunne M. G., Kappatou A., Putterich T., Stroth U., and Viezzer E.

Abstract

A newly installed core charge exchange recombination spectroscopy (CXRS) diagnostic at ASDEX Upgrade (AUG) enables the evaluation of the core poloidal rotation (upol) through the inboard-outboard asymmetry of the toroidal rotation with an accuracy of 0.5 to 1 km s-1. Using this technique, the total plasma flow has been measured in Ohmic L-mode plasmas across the transition from the linear to saturated ohmic confinement (LOC-SOC) regimes. The core poloidal rotation of the plasma around mid-radius is found to be always in the ion diamagnetic direction, in disagreement with neoclassical (NC) predictions. The edge rotation is found to be electron-directed and consistent with NC codes. This measurement provides as well the missing ingredient to evaluate the core E × B velocity (uE×B) from data only, which can then be compared to measurements of the perpendicular velocity of the turbulent fluctuations (u) to gain information on the turbulent phase velocity (vph). The non neoclassical upol from CXRS leads to good agreement between uE×B and u indicating that vph is small and at similar values as found with gyrokinetic simulations. Moreover, the data shows a shift of vph in the ion-diamagnetic direction at the edge after the transition from LOC to SOC consistent with a change in the dominant turbulence regime. The upgrade of the core CXRS system provides as well a deeper insight into the intrinsic rotation. This paper shows that the reversal of the core toroidal rotation occurs clearly after the LOC-SOC transition and concomitant with the peaking of the electron density.

Published
2018

32. Inter-ELM Fluctuations and Flows and their evolution when approaching the density limit in the ASDEX Upgrade tokamak

Author

Hennequin, Pascale, Laggner, F., Mink, F., Wolfrum, E., Trier, Elisée, Eich, T., Bernert, M., Birkenmeier, G., Conway, G. D., Happel, T., Honoré, Cyrille, Gürcan, Özgür, Manz, P., Medvedeva, A., Stroth, U., ASDEX Upgrade Team, The, EUROfusion MST1 Team, The, Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Max Planck Institute for Plasma physics (IPP-MPG), and Max-Planck-Gesellschaft

Subjects
[PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017

33. Isotope dependence of limit-cycle oscillations in ASDEX Upgrade plasmas

Author

Birkenmeier, G., Happel, T., Hennequin, Pascale, Conway, G. D., Manz, P., Cavedon, M., Medvedeva, A., Ryter, F., Wolfrum, E., Stroth, U., ASDEX Upgrade Team, The, Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)

Subjects
[PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017

34. Validation studies of ion-scale GENE simulations in L-mode plasmas at ASDEX Upgrade

Author

Freethy, Simon, Creely, A. J., Görler, T., Conway, G. D., Happel, T., Hennequin, Pascale, Pinzón, J R, Prisiazhniuk, D., Stroth, U., White, A. E., ASDEX Upgrade Team, The, Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)

Subjects
[PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017

35. Investigation of turbulence properties via spectral broadening of Doppler reflectometry signals in ASDEX Upgrade

Author

Conway, G. D., Lechte, C., Hennequin, Pascale, Simon, P., ASDEX Upgrade Team, The, Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)

Subjects
[PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017

36. Isotope dependence of limit-cycle oscillations in ASDEX Upgrade plasmas

Author

Birkenmeier G., Happel T., Hennequin P., Conway G. D., Manz P., Cavedon M., Medvedeva A., Ryter F., Wolfrum E., Stroth U., ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, Bret, A, Fajardo, M, Westerhof, E, Melzer, A, Dromey, B, Riconda, C, Birkenmeier, G, Happel, T, Hennequin, P, Conway, G, Manz, P, Cavedon, M, Medvedeva, A, Ryter, F, Wolfrum, E, and Stroth, U

Subjects
Plasma
Published
2017

37. Understanding of wavenumber spectra measured by Doppler reflectometry through simulation and related estimation of wave-plasma interaction regimes

Author

Happel, T., Görler, T., Hennequin, Pascale, Lechte, C., Pinzón, J R, Bernert, M., Conway, G. D., Freethy, Simon, Honoré, Cyrille, Stroth, U., ASDEX Upgrade Team, The, Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)

Subjects
[PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017

39. H-mode power threshold studies in mixed ion species plasmas at ASDEX Upgrade.

Author

Plank, U., Pütterich, T., Angioni, C., Cavedon, M., Conway, G. D., Fischer, R., Happel, T., Kappatou, A., McDermott, R. M., Schneider, P. A., Tardini, G., Weiland, M., and team, ASDEX Upgrade

Subjects
HYDROGEN plasmas, HEAT flux, IONS, HELIUM plasmas, DEUTERIUM
Abstract

Understanding the dependence of the H-mode power threshold, on the main ion composition is crucial for H-mode operation in ITER. In this work, H-mode power threshold studies conducted at ASDEX Upgrade are presented. These were performed in hydrogen plasmas with helium doping and in mixed hydrogen-deuterium plasmas. stays constant on the level of pure hydrogen in hydrogen plasmas with helium doping up to. Power balance calculations with the transport code ASTRA show that the edge ion heat flux at the L-H transition is independent of helium concentration and applied auxiliary heating, supporting that a critical edge ion heat flux is needed to enter H-mode. A non-linear dependence of on the relative hydrogen content is found. and the edge ion heat flux are constant at the level of pure deuterium for between 0 and 0.5 and constant on the level of pure hydrogen for between 0.8 and 1. [ABSTRACT FROM AUTHOR]

Published
2020
Full Text
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44. The I-mode confinement regime at ASDEX Upgrade: global propert ies and characterization of strongly intermittent density fluctuations

Author

Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, European Union (UE), Happel, T., Manz, P., Ryter, F., Bernert, M., Dunne, M. G., Hennequin, P., Hetzenecker, A., Stroth, U., Conway, G. D., Guimarais, L., Honoré, C., Viezzer, Eleonora, Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, European Union (UE), Happel, T., Manz, P., Ryter, F., Bernert, M., Dunne, M. G., Hennequin, P., Hetzenecker, A., Stroth, U., Conway, G. D., Guimarais, L., Honoré, C., and Viezzer, Eleonora

Abstract

Properties of the I­mode confinement regime on the ASDEX Upgrade tokamak are summarized. A weak dependence of the power threshold for the L­I transition on the toroidal magnetic field strength is found. During improved confinement, the edge radial electric field well deepens. Stability calculations show that the I­mode pedestal is peeling­ballooning stable. Turbulence investigations reveal strongly intermittent density fluctuations linked to the weakly coherent mode in the confined plasma, which become stronger as the confinement quality increases. Across all investigated structure sizes ( ≈ ⊥ k 5 – 12 cm − 1 , with ⊥ k the perpendicular wavenumber of turbulent density fluctuations), the intermittent turbulence bursts are observed. Comparison with bolometry data shows that they move poloidally toward the X­point and finally end up in the divertor. This might be indicative that they play a role in inhibiting the density profile growth, such that no pedestal is formed in the edge density profile.

Published
2017

45. Isotope dependence of limit-cycle oscillations in ASDEX Upgrade plasmas

Author

Bret, A, Fajardo, M, Westerhof, E, Melzer, A, Dromey, B, Riconda, C, Birkenmeier, G, Happel, T, Hennequin, P, Conway, G, Manz, P, Cavedon, M, Medvedeva, A, Ryter, F, Wolfrum, E, Stroth, U, Birkenmeier G., Happel T., Hennequin P., Conway G. D., Manz P., Cavedon M., Medvedeva A., Ryter F., Wolfrum E., Stroth U., Bret, A, Fajardo, M, Westerhof, E, Melzer, A, Dromey, B, Riconda, C, Birkenmeier, G, Happel, T, Hennequin, P, Conway, G, Manz, P, Cavedon, M, Medvedeva, A, Ryter, F, Wolfrum, E, Stroth, U, Birkenmeier G., Happel T., Hennequin P., Conway G. D., Manz P., Cavedon M., Medvedeva A., Ryter F., Wolfrum E., and Stroth U.

Published
2017

46. Density profile and turbulence evolution during L-H transition studied with the Ultra-fast swept reflectometer on ASDEX Upgrade

Author

Medvedeva, Anna, Birkenmeier, G., Bottereau, C., Cavedon, M., Clairet, F., Conway, G. D., Hennequin, Pascale, Heuraux, S., Molina, D., Silva, A., Stroth, U., ASDEX Upgrade Team, The, Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)

Subjects
[PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2016

47. Turbulence intermittency linked to the weakly coherent mode in ASDEX Upgrade I-mode plasmas

Author

Happel, T., Manz, P., Ryter, F., Hennequin, Pascale, Hetzenecker, A., Conway, G. D., Luis Guimarais, Honoré, Cyrille, Stroth, U., Viezzer, E., The Asdex Upgrade, Team, Laboratoire de Physique des Plasmas (LPP), Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Physics, Nuclear and High Energy Physics, Tokamak, Turbulence, Mode (statistics), Plasma, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, law.invention, Temperature gradient, Amplitude, ASDEX Upgrade, law, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Intermittency, 0103 physical sciences, Atomic physics, 010306 general physics
Abstract

This letter shows for the first time a pronounced increase of extremely intermittent edge density turbulence behavior inside the confinement region related to the I-mode confinement regime in the ASDEX Upgrade tokamak. With improving confinement, the perpendicular propagation velocity of density fluctuations in the plasma edge increases together with the intermittency of the observed density bursts. Furthermore, it is shown that the weakly coherent mode, a fluctuation feature generally observed in I-mode plasmas, is connected to the observed bursts. It is suggested that the large amplitude density bursts could be generated by a non-linearity similar to that in the Korteweg–de-Vries equation which includes the radial temperature gradient.

Published
2016

48. L-H transition physics in hydrogen and deuterium: key role of the edge radial electric field and ion heat flux

Author

Asdex Upgrade Team T., Ryter F., Cavedon M., Happel T., McDermott R. M., Viezzer E., Conway G. D., Fischer R., Kurzan B., Putterich T., Tardini G., Willensdorfer M., ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, Asdex Upgrade Team, T, Ryter, F, Cavedon, M, Happel, T, Mcdermott, R, Viezzer, E, Conway, G, Fischer, R, Kurzan, B, Putterich, T, Tardini, G, and Willensdorfer, M

Subjects
Physics, Tokamak, ion heat flux, Hydrogen, Plasma parameters, radial electric field, chemistry.chemical_element, Plasma, Condensed Matter Physics, L-H transition, 7. Clean energy, 01 natural sciences, 010305 fluids & plasmas, Ion, law.invention, Nuclear Energy and Engineering, ASDEX Upgrade, chemistry, Deuterium, Heat flux, Physics::Plasma Physics, law, 0103 physical sciences, Atomic physics, 010306 general physics
Abstract

Previous work carried out in the ASDEX Upgrade tokamak on the role of the edge radial electric field and ion heat flux in the L-H transition physics in deuterium plasmas has been extended in hydrogen plasmas. Similar discharges were performed in the two gases providing a detailed comparison of the edge kinetic profiles and heat fluxes in L-mode up to the L-H transition, as the heating power is increased. At the L-H transition, the edge ion heat flux just inside the separatrix is about two times higher in hydrogen than in deuterium. However, the ion plasma parameters at the plasma edge, T i and , as well as the radial electric field well, are found to be very similar in the two gases. The transport analysis based on this data reveals that, at the L-H transition, the ion heat transport at the plasma edge is about two times higher in hydrogen than in deuterium, in agreement with the well-known isotope effect of confinement and transport. This indicates that the higher power threshold in hydrogen is mainly due to the higher ion heat transport in this gas.

Published
2016
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50. Measurement of the E×B velocity across the LOC-SOC transition

Author

Lebschy A., McDermott R. M., Angioni C., Geiger B., Cavedon M., Conway G. D., Dux R., Fable E., Happel T., Kappatou A., Medvedeva A., Putterich T., Prisiazhniuk D., Ryter F., Stroth U., Viezzer E., Poedts, S, Fajardo, M, Giruzzi, G, Gans, T, Vennekens, N, Mantica, P, Lebschy, A, Mcdermott, R, Angioni, C, Geiger, B, Cavedon, M, Conway, G, Dux, R, Fable, E, Happel, T, Kappatou, A, Medvedeva, A, Putterich, T, Prisiazhniuk, D, Ryter, F, Stroth, U, and Viezzer, E

Subjects
Plasma
Published
2016

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