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Relaxed magnetohydrodynamics with ideal Ohm's law constraint

Published online by Cambridge University Press:  04 February 2022

R.L. Dewar*
Affiliation:
Mathematical Sciences Institute, The Australian National University, Canberra, ACT 2601, Australia
Z.S. Qu
Affiliation:
Mathematical Sciences Institute, The Australian National University, Canberra, ACT 2601, Australia
*
Email address for correspondence: robert.dewar@anu.edu.au

Abstract

The gap between a recently developed dynamical version of relaxed magnetohydrodynamics (RxMHD) and ideal MHD (IMHD) is bridged by approximating the zero-resistivity ‘ideal’ Ohm's law (IOL) constraint using an augmented Lagrangian method borrowed from optimization theory. The augmentation combines a pointwise vector Lagrange multiplier method and global penalty function method and can be used either for iterative enforcement of the IOL to arbitrary accuracy, or for constructing a continuous sequence of magnetofluid dynamics models running between RxMHD (no IOL) and weak IMHD (IOL almost everywhere). This is illustrated by deriving dispersion relations for linear waves on an MHD equilibrium.

Type
Research Article
Copyright
Copyright © The Author(s), 2022. Published by Cambridge University Press

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