April 4-6

Abstract Details

files Add files


Author: Patrick S. Kim
Requested Type: Consider for Invited
Submitted: 2022-03-03 16:09:21

Co-authors: A.M. Wright, N.M. Ferraro, S.R. Hudson

Contact Info:
8279 Paint Branch Dr
College Park, MD   20740
United States

Abstract Text:
Small-amplitude symmetry-breaking perturbations such as resonant magnetic perturbations (RMPs) and error fields play important roles in the design of tokamaks and stellarators [1]. We demonstrate the conditions under which the Stepped Pressure Equilibrium Code (SPEC)[2] can be used to efficiently calculate the nonlinear, non-ideal plasma response to an externally applied resonant magnetic perturbation, in experimentally relevant geometry. Specifically, by comparing to nonlinear simulations of the extended-MHD code M3D-C1 [3], we show that the model can recover the plasma response to a (m=2,n=1) RMP field in the weakly nonlinear regime. SPEC calculates Multi-Region Relaxed MHD (MRxMHD) equilibria [2] that allow for changes to magnetic topology that can yield island formation and chaotic field lines. Presently, there exist few codes that can calculate both the non-ideal and nonlinear plasma response to these 3D fields, and these codes are usually very computationally expensive. This work suggests that MRxMHD can be a useful tool for efficiently calculating 3D fields in optimization and fusion plasma design.

[1] J. Callen, “Effects of 3D magnetic perturbations on toroidal plasmas,” Nuclear Fusion, vol. 51, no. 9, p. 094026, 2011.
[2] S. R. Hudson, R. L. Dewar, G. Dennis, et al., “Computation of multi-region relaxed magneto-hydrodynamic equilibria,” Physics of Plasmas, vol. 19, no. 11, pp. 1–18, 2012.
[3] S. C. Jardin, N. Ferraro, J. Breslau, and J. Chen, “Multiple timescale calculations of saw-teeth and other global macroscopic dynamics of tokamak plasmas,” Computational Science & Discovery, vol. 5, no. 1, p. 014002, 2012.