Linear simulations of the cylindrical Richtmyer-Meshkov instability in magnetohydrodynamics

Abstract
Numerical simulations and analysis indicate that the Richtmyer-Meshkov instability(RMI) is suppressed in ideal magnetohydrodynamics(MHD) in Cartesian slab geometry. Motivated by the presence of hydrodynamic instabilities in inertial confinement fusion and suppression by means of a magnetic field, we investigate the RMI via linear MHD simulations in cylindrical geometry. The physical setup is that of a Chisnell-type converging shock interacting with a density interface with either axial or azimuthal (2D) perturbations. The linear stability is examined in the context of an initial value problem (with a time-varying base state) wherein the linearized ideal MHD equations are solved with an upwind numerical method. Linear simulations in the absence of a magnetic field indicate that RMI growth rate during the early time period is similar to that observed in Cartesian geometry. However, this RMI phase is short-lived and followed by a Rayleigh-Taylor instability phase with an accompanied exponential increase in the perturbation amplitude. We examine several strengths of the magnetic field (characterized by β=2p/B^2_r) and observe a significant suppression of the instability for β ≤ 4. The suppression of the instability is attributed to the transport of vorticity away from the interface by Alfvén fronts.

Citation
Linear simulations of the cylindrical Richtmyer-Meshkov instability in magnetohydrodynamics 2016, 28 (3):034106 Physics of Fluids

Acknowledgements
This work was supported by the KAUST Office of Sponsored Research under Award No. URF/1/2162-01.

Publisher
AIP Publishing

Journal
Physics of Fluids

DOI
10.1063/1.4943162

Additional Links
http://scitation.aip.org/content/aip/journal/pof2/28/3/10.1063/1.4943162

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