May 8-10

Abstract Details

files Add files

Abstracts

Author: Eric C Howell
Requested Type: Poster
Submitted: 2023-03-31 12:04:24

Co-authors: T. Cote, C. Zhao, D. Orlov, M.J. Choi, J. Heo, S.K. Kim, J.K. Park, S.M. Yang

Contact Info:
Tech-X Corporation
5621 Arapahoe Ave, Ste A
Boulder, CO   80303
United States

Abstract Text:
Unmitigated ELMs produce a cyclic heat load that jeopardizes the success of ITER and a future tokamak burning plasma pilot plant. ITER’s primary solution relies on the application of external 3D magnetic perturbations. The perturbations that are resonant near the top of the pedestal can reconnect, changing the magnetic field topology, and enhancing transport. The enhanced transport limits the pedestal growth prior to violating MHD stability limits. Thus validated models that accurately compute the plasma response to the resonant magnetic perturbations (RMP) are vital to the success of ITER.
KSTAR discharges are used to test the linear and nonlinear MHD responses in NIMROD and M3D-C1. Initial comparisons use inner wall limited L-mode discharges where the in-vessel control coils (IVCC) are used to apply a predominantly n=1 magnetic perturbation. The currents in the IVCC coils are linearly ramped in time, and ECEI measurements provide experimental measurements of the resulting 2/1 island in both strongly screened and locked states. During times prior to locking linear and nonlinear models predict that the response plasma is strongly in agreement with the experiment. After the plasma has locked, linear models show penetration of the resonant fields; however, M3D-C1 calculations show more reconnected flux at the 2/1 surface, resulting in a larger island than NIMROD. Efforts to reconcile this disagreement are discussed. Initial NIMROD results using a second H-mode KSTAR case with rotating n=1 RMPs are presented.

This work is supported by US DOE under grants: DE-SC0021185 and DE-FG02-05ER54809

Comments: