# – Niels Bohr Institute - University of Copenhagen

## Shearing box simulations in the Rayleigh unstable regime

Research output: Contribution to journalJournal articleResearchpeer-review

Farrukh Nauman, Eric G. Blackman

We study the stability properties of Rayleigh unstable flows both in the purely hydrodynamic and magnetohydrodynamic (MHD) regimes for two different values of the shear $q=2.1, 4.2$ ($q = - d\ln\Omega / d\ln r$) and compare it with the Keplerian case $q=1.5$. The Rayleigh stability criterion states that hydrodynamic shear flows are stable for $q2$ regime as the volume averaged velocities ($k=0$ mode) are unstable in this regime but the advantage of using a pseudospectral code is that the $k=0$ mode is conserved. We find that the $q>2$ regime is unstable to turbulence both in the hydrodynamic and in the MHD limit (with an initially weak magnetic field). In the $q>2$ regime, the velocity fluctuations dominate the magnetic fluctuations whereas in the $q2$ regime the instability produces primarily velocity fluctuations that cause magnetic fluctuations, with the causality reversed for the \$q
Original language English Monthly Notices of the Royal Astronomical Society 467 2 1652-1660 0035-8711 10.1093/mnras/stx209 Published - 1 May 2017

### Research areas

• Astrophysics - Solar and Stellar Astrophysics, Physics - Plasma Physics

ID: 166633220