Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published January 1, 2016 | Published + Submitted
Journal Article Open

Accurate, meshless methods for magnetohydrodynamics

Abstract

Recently, we explored new meshless finite-volume Lagrangian methods for hydrodynamics: the 'meshless finite mass' (MFM) and 'meshless finite volume' (MFV) methods; these capture advantages of both smoothed particle hydrodynamics (SPH) and adaptive mesh refinement (AMR) schemes. We extend these to include ideal magnetohydrodynamics (MHD). The MHD equations are second-order consistent and conservative. We augment these with a divergence-cleaning scheme, which maintains ∇⋅B≈0∇⋅B≈0. We implement these in the code GIZMO, together with state-of-the-art SPH MHD. We consider a large test suite, and show that on all problems the new methods are competitive with AMR using constrained transport (CT) to ensure ∇⋅B=0∇⋅B=0. They correctly capture the growth/structure of the magnetorotational instability, MHD turbulence, and launching of magnetic jets, in some cases converging more rapidly than state-of-the-art AMR. Compared to SPH, the MFM/MFV methods exhibit convergence at fixed neighbour number, sharp shock-capturing, and dramatically reduced noise, divergence errors, and diffusion. Still, 'modern' SPH can handle most test problems, at the cost of larger kernels and 'by hand' adjustment of artificial diffusion. Compared to non-moving meshes, the new methods exhibit enhanced 'grid noise' but reduced advection errors and diffusion, easily include self-gravity, and feature velocity-independent errors and superior angular momentum conservation. They converge more slowly on some problems (smooth, slow-moving flows), but more rapidly on others (involving advection/rotation). In all cases, we show divergence control beyond the Powell 8-wave approach is necessary, or all methods can converge to unphysical answers even at high resolution.

Additional Information

© 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2015 September 17. Received 2015 September 17; in original form 2015 April 17. First published online November 2, 2015. We thank Paul Duffell, Jim Stone, Evghenii Gaburov, Ryan O'Leary, Romain Teyssier, Colin McNally, our referee Daniel Price, and many others for enlightening discussions and the initial studies motivating this paper. Support for PFH was provided by the Gordon and Betty Moore Foundation through Grant #776 to the Caltech Moore Center for Theoretical Cosmology and Physics, an Alfred P. Sloan Research Fellowship, NASA ATP Grant NNX14AH35G, and NSF Collaborative Research Grant #1411920. Numerical calculations were run on the Caltech compute cluster 'Zwicky' (NSF MRI award #PHY-0960291) and allocation TG-AST130039 granted by the Extreme Science and Engineering Discovery Environment (XSEDE) supported by the NSF.

Attached Files

Published - MNRAS-2016-Hopkins-51-88.pdf

Submitted - 1505.02783v2.pdf

Files

1505.02783v2.pdf
Files (22.6 MB)
Name Size Download all
md5:6f8649713627e6ebcc85d29f528d01aa
10.9 MB Preview Download
md5:b618215893ff188a9e16175509fed202
11.7 MB Preview Download

Additional details

Created:
August 20, 2023
Modified:
October 23, 2023