Abstract Details
Abstracts
Author: Robert L. DEWAR
Requested Type: Poster
Submitted: 2019-02-23 04:19:21
Co-authors: N. Sato, J.W. Burby, Z. Qu
Contact Info:
The Australian National University
MSI, 3.53 Bldg #145, Science R
Acton, ACT 2601
Australia
Abstract Text:
The time-dependent, action-based formulation [1] of Multiregion Relaxed MHD (MRxMHD) includes Taylor relaxation, but it does not incorporate a relaxation model for the fluid. This shortcoming severely limits the computational benefits of dynamical MRxMHD, which was intended as a computationally-efficient alternative to the usual MHD model. A previous attempt at accounting for fluid relaxation within the action principle by constraining the fluid helicity [1] led to paradoxical results [2]. We show that an alternative “phase-space Lagrangian” (PSL) formulation does away with those unphysical artifacts, and thereby leads to a physically-plausible relaxed-fluid variant of MRxMHD. The dynamical equations resulting from two slightly different PSL formulations are compared, and extension to include cross-helicity is discussed.
[1] R.L. Dewar, Z. Yoshida, A. Bhattacharjee and S.R. Hudson, J. Plasma Phys., 81, 515810604-1–22, (2015).
[2] N. Sato and R.L. Dewar, arxiv:1708.06193, (2017)
Some of this work was supported by the Australian Research Council grant DP170102606 and some by the National Science Foundation grant DMS-1440140 while RLD and JWB were in residence at the Mathematical Sciences Research Institute in Berkeley,in 2019.
This presentation was also partially supported by a grant from the Simons Foundation/SFARI (560651, AB).
Comments:
Suggested grouping of MRxMHD posters:
1. Zhisong Qu: Multi-region relaxed MHD (MRxMHD) with flow
2. Arunav Kumar: Stability Analysis of MRxMHD in Cylindrical Geometry
3. This poster
