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Local simulations of MRI turbulence with meshless methods

Deng, Hongping and Mayer, Lucio and Latter, Henrik and Hopkins, Philip F. and Bai, Xue-Ning (2019) Local simulations of MRI turbulence with meshless methods. Astrophysical Journal Supplement Series, 241 (2). Art. No. 26. ISSN 1538-4365. http://resolver.caltech.edu/CaltechAUTHORS:20190206-105658617

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Abstract

The magneto-rotational instability (MRI) is one of the most important processes in sufficiently ionized astrophysical disks. Grid-based simulations, especially those using the local shearing box approximation, provide a powerful tool to study the nonlinear turbulence the MRI produces. On the other hand, meshless methods have been widely used in cosmology, galactic dynamics, and planet formation, but have not been fully deployed on the MRI problem. We present local unstratified and vertically stratified MRI simulations with two meshless MHD schemes: a recent implementation of smoothed-particle magnetohydrodynamics (SPH MHD), and a meshless finite-mass (MFM) MHD scheme with constrained gradient divergence cleaning, as implemented in the GIZMO code. Concerning variants of the SPH hydro force formulation, we consider both the "vanilla" SPH and the PSPH variant included in GIZMO. We find, as expected, that the numerical noise inherent in these schemes significantly affects turbulence. Furthermore, a high-order kernel, free of the pairing instability, is necessary. Both schemes adequately simulate MRI turbulence in unstratified shearing boxes with net vertical flux. The turbulence, however, dies out in zero-net-flux unstratified boxes, probably due to excessive numerical dissipation. In zero-net-flux vertically stratified simulations, MFM can reproduce the MRI dynamo and its characteristic butterfly diagram for several tens of orbits before ultimately decaying. In contrast, extremely strong toroidal fields, as opposed to sustained turbulence, develop in equivalent simulations using SPH MHD. The latter unphysical state is likely caused by a combination of excessive artificial viscosity, numerical resistivity, and the relatively large residual errors in the divergence of the magnetic field.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.3847/1538-4365/ab0957DOIArticle
http://arxiv.org/abs/1901.05190arXivDiscussion Paper
ORCID:
AuthorORCID
Deng, Hongping0000-0001-6858-1006
Hopkins, Philip F.0000-0003-3729-1684
Bai, Xue-Ning0000-0001-6906-9549
Additional Information:© 2019 The American Astronomical Society. Received 2018 October 31; revised 2019 February 13; accepted 2019 February 20; published 2019 April 1. We thank Matthew Bate, Daniel Price, Stephen Rosswog, Jim Stone, James Wadsley, Sijing Shen, and Robert Wissing for useful discussions. We acknowledge support from the Swiss National Science Foundation via the NCCR PlanetS. Support for P.F.H. was provided by an Alfred P. Sloan Research Fellowship, NSF Collaborative Research grant #1715847 and CAREER grant #1455342, and NASA grants NNX15AT06G, JPL 1589742, and 17-ATP17-0214. Software: GIZMO code (Hopkins 2015), VisIt (Childs et al. 2012).
Group:TAPIR
Funders:
Funding AgencyGrant Number
Swiss National Science Foundation (SNSF)UNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
NSFAST-1715847
NSFAST-1455342
NASANNX15AT06G
JPL1589742
JPL17-ATP17-0214
Subject Keywords:accretion, accretion disks – magnetohydrodynamics (MHD) – methods: numerical – turbulence
Record Number:CaltechAUTHORS:20190206-105658617
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20190206-105658617
Official Citation:Hongping Deng et al 2019 ApJS 241 26
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:92735
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:07 Feb 2019 15:41
Last Modified:01 Apr 2019 16:58

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