Kinetic ballooning modes in tokamaks and stellarators

• DOI: 10.1017/s0022377818001186
• Publication Date: 2018-12-11T05:08:22Z
• Authors: K. Aleynikova; A. Zocco; P. Xanthopoulos; P. Helander; C. Nührenberg
• Keywords: Unicode; Diamagnetism; Ballooning; Wendelstein 7-X

Kinetic ballooning modes (KBMs) are investigated by means of linear electromagnetic gyrokinetic (GK) simulations in the stellarator Wendelstein 7-X (W7-X), for high- $\unicode[STIX]{x1D6FD}$ plasmas, where is ratio thermal to magnetic plasma pressure. The analysis shows suppression ion-temperature-gradient (ITG) and trapped particle (TEM) finite- effects destabilization KBMs at high . results compared with a generic tokamak case. We show that, large pressure gradients, frequency evaluated GENE code agreement analytical prediction diamagnetic modification ideal magnetohydrodynamic limit W7-X general geometry. Thresholds KBM predicted different equilibrium configurations. discuss relation these thresholds (MHD) stability properties corresponding equilibria.