Incorporating ambipolar and ohmic diffusion in the AMR MHD code

J. Masson, R. Teyssier, C. Mulet-Marquis, P. Hennebelle, G. Chabrier

Research output: Contribution to journalArticlepeer-review

38 Scopus citations

Abstract

We have implemented non-ideal magnetohydrodynamics (MHD) effects in the adaptive mesh refinement code RAMSES, namely, ambipolar diffusion and Ohmic dissipation, as additional source terms in the ideal MHD equations. We describe in details how we have discretized these terms using the adaptive Cartesian mesh, and how the time step is diminished with respect to the ideal case, in order to perform a stable time integration. We have performed a large suite of test runs, featuring the Barenblatt diffusion test, the Ohmic diffusion test, the C-shock test, and the Alfvén wave test. For the latter, we have performed a careful truncation error analysis to estimate the magnitude of the numerical diffusion induced by our Godunov scheme, allowing us to estimate the spatial resolution that is required to address non-ideal MHD effects reliably. We show that our scheme is second-order accurate, and is therefore ideally suited to study non-ideal MHD effects in the context of star formation and molecular cloud dynamics.

Original languageEnglish (US)
Article number24
JournalAstrophysical Journal, Supplement Series
Volume201
Issue number2
DOIs
StatePublished - Aug 2012
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • ISM: magnetic fields
  • methods: numerical
  • stars: formation

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