Electromagnetic pressure-gradient-driven instabilities with moderate high mode numbers in tokamak plasmas
Abstract
Pressure gradient-driven instabilities are investigated in tokamak plasmas using the global gyrokinetic code EUTERPE emphasizing the role of moderate high mode numbers. As the normalized plasma pressure β is increased, there is a well-known, sudden transition from ion-temperature-gradient (ITG) instabilities to kinetic ballooning modes (KBM), if the magnetohydrodynamic (MHD) geometry is held fixed. However, if the equilibrium field is recomputed for each value of β, so that the equilibrium is consistent with the stability calculation, the transition can disappear. In a number of cases, we are only able to find an ITG-KBM transition if inconsistent equilibria are used. In the MHD unstable regime, gyrokinetic simulations and MHD stability calculations show good agreement for moderate ratios of ion temperature gradient to density gradient and small values of the ion gyro-radius. Otherwise, non-MHD contributions are important, such as the diamagnetic stabilization and ion wave--particle resonant effects.
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BibTeX
@misc{narbutt2026electromagnetic,
title = {{Electromagnetic pressure-gradient-driven instabilities with moderate high mode numbers in tokamak plasmas}},
author = {Yann Narbutt and Ksenia Aleynikova and Matthias Borchardt and Thomas Hayward-Schneider and Ralf Kleiber and Axel Könies and Alexey Mishchenko and Carolin Nührenberg and Edilberto Sánchez},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.28367},
eprint = {2608.28367},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.28367},
note = {CC BY-NC-SA 4.0},
}
RIS
TY - UNPB
TI - Electromagnetic pressure-gradient-driven instabilities with moderate high mode numbers in tokamak plasmas
AU - Yann Narbutt
AU - Ksenia Aleynikova
AU - Matthias Borchardt
AU - Thomas Hayward-Schneider
AU - Ralf Kleiber
AU - Axel Könies
AU - Alexey Mishchenko
AU - Carolin Nührenberg
AU - Edilberto Sánchez
PY - 2026
DA - 2026/08/28
PB - arXiv
DO - 10.48550/arxiv.2608.28367
UR - https://arxiv.org/abs/2608.28367
AB - Pressure gradient-driven instabilities are investigated in tokamak plasmas using the global gyrokinetic code EUTERPE emphasizing the role of moderate high mode numbers. As the normalized plasma pressure β is increased, there is a well-known, sudden transition from ion-temperature-gradient (ITG) instabilities to kinetic ballooning modes (KBM), if the magnetohydrodynamic (MHD) geometry is held fixed. However, if the equilibrium field is recomputed for each value of β, so that the equilibrium is consistent with the stability calculation, the transition can disappear. In a number of cases, we are only able to find an ITG-KBM transition if inconsistent equilibria are used. In the MHD unstable regime, gyrokinetic simulations and MHD stability calculations show good agreement for moderate ratios of ion temperature gradient to density gradient and small values of the ion gyro-radius. Otherwise, non-MHD contributions are important, such as the diamagnetic stabilization and ion wave--particle resonant effects.
ER -