Hydromagnetic Instability in plane Couette Flow

TL;DR

This paper investigates a new type of hydromagnetic instability in compressible plane Couette flow, showing it can occur under various conditions and dominate other instabilities even in strong magnetic fields.

Contribution

It introduces a novel instability mechanism in compressible magnetic Couette flow that can operate in strong magnetic fields and has rapid growth times.

Findings

Instability occurs with magnetic field components perpendicular to flow.

Can operate in both laboratory and astrophysical flows.

Growth time can be as short as 10 shear timescales.

Abstract

We study the stability of a compressible magnetic plane Couette flow and show that compressibility profoundly alters the stability properties if the magnetic field has a component perpendicular to the direction of flow. The necessary condition of a newly found instability can be satisfied in a wide variety of flows in laboratory and astrophysical conditions. The instability can operate even in a very strong magnetic field which entirely suppresses other MHD instabilities. The growth time of this instability can be rather short and reach $\sim 10$ shear timescales.