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arXiv · 1711.08849

Rossby Vortices in Thin Magnetized Accretion Discs

Loren Matilsky·Sergei Dyda·Richard V. E. Lovelace·Patrick Lii
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Abstract

We study the Rossby wave instability (RWI) in a thin accretion disc threaded by an initially toroidal magnetic field using the magnetohydrodynamics (MHD) code PLUTO. We find that for plasma $10^1 < \beta < 10^3$ , the growth rate and late-time density are suppressed, whereas for plasma $\beta > 10^3$, the magnetic field has negligible effect. The initially toroidal field is twisted inside the vortex and expelled at late times. This creates a radially directed field outside the vortex region, which can be understood via a simple kinematic model of a magnetic field in a rotating fluid and may be observable via polarised dust emission.

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Loren Matilsky, Sergei Dyda, Richard V. E. Lovelace, Patrick Lii. 2017-11-24. Rossby Vortices in Thin Magnetized Accretion Discs. https://doi.org/10.1093/mnras%2Fsty2076

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