Rossby Wave Instability in Accretion Discs with Large-Scale Poloidal Magnetic Fields

Abstract

We study the effect of large-scale magnetic fields on the non-axisymmetric Rossby wave instability (RWI) in accretion discs. The instability develops around a density bump, which is likely present in the transition region between the active zone and dead zone of protoplanetary discs. Previous works suggest that the vortices resulting from the RWI may facilitate planetesimal formation and angular momentum transport. We consider discs threaded by a large-scale poloidal magnetic field, with a radial field component at the disc surface. Such field configurations may lead to the production of magnetic winds or jets. In general, the magnetic field can affect the RWI even when it is sub-thermal (plasma $\beta \sim 10$). For infinitely thin discs, the instability can be enhanced by about 10 percent. For discs with finite thickness, with a radial gradient of the magnetic field strength, the RWI growth rate can increase significantly (by a factor of $\sim 2$) as the field approaches equipartition ($\beta \sim 1$). Our result suggests that the RWI can continue to operate in discs that produce magnetic winds.

Accepted for publication in MNRAS, 7 pages, 8 figures

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Cited by in corpus (12)

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• Rossby Wave Instability in Astrophysical Discs
• Three-dimensional Global Simulations of Type-II Planet-disk Interaction with a Magnetized Disk Wind: I. Magnetic Flux Concentration and Gap Properties
• Vortex cycles at the inner edges of dead zones in protoplanetary disks
• Physics in Very Strong Magnetic Fields: Introduction and Overview
• Corotation resonance and overstable oscillations in black-hole accretion discs: general-relativistic calculations
• Rossby-wave instability in viscous discs
• Simulations of Overstable Inertial-acoustic Modes in Black-Hole Accretion Discs
• Density streams in the disc winds of Classical T Tauri stars
• Rossby Vortices in Thin Magnetized Accretion Discs
• Rossby wave instability in weakly ionized protoplanetary disks. II. radial B-fields
• Inertial-Acoustic Oscillations of Black-Hole Accretion Discs with Large-Scale Poloidal Magnetic Fields