Abstract Details
Abstracts
Author: Jacobo Varela Rodriguez
Requested Type: Poster
Submitted: 2025-03-04 10:21:38
Co-authors: J. Varela, J. Garcia, B. Breizman, S.E. Sharapov, F. Waelbroeck, D. Spong, L. Garcia, Y. Ghai, S. Ohdachi, K. Y. Watanabe and R. Seki
Contact Info:
IFS UT-Austin
2515 Speedway
Austin, TX 78712
United States
Abstract Text:
The present study is dedicated to analyze energetic particle modes (EPM) in fusion devices. The aim of the analysis is reproducing the EPM frequency down sweeping and the transition from energetic particle (EP) to current or pressure gradient driven instabilities observed in the experiments. In addition, the shear flows generation during EPM decay is analyzed. Two test cases are considered, fish-bones in a JET configuration and energetic-ion-driven resistive interchange modes (called EIC in X. Du et al Nucl. Fusion 56 016002, 2006) in LHD. A set of nonlinear simulations using the gyro-fluid code FAR3d are performed removing the EP drive along the saturation phase of fish-bones / EIC, analyzing the EPMs decay phase. The simulations reproduce the EPMs frequency down-sweeping observed in the experiments along the instability transition from the EP driven fish-bones to the current driven 1/1 internal kink in the JET case as well as the transition from the EP driven EIC to the pressure gradient driven 1/1 resistive interchange mode (RIC) in LHD model. The simulations show the generation of shear flows during the EPM decay and the presence of radial electric fields in the plasma radial location where the fish-bone / EIC are destabilized. The energy transfer from the fish-bones / EIC towards the thermal plasma and the EP population losses / radial redistribution cause a local modification of the plasma electrostatic potential as well as the generation of radial electric fields and shear flows. Consequently, the EPM decay and stabilization is affected by the generation of shear flows, thus a correct description of the EPMs dynamic requires considering the feedback effect between EP driven modes and thermal plasma, reproducing the self-consistent evolution of the EP and thermal plasma profiles.
Characterization: 1.0
Comments: