The Richtmyer-Meshkov Instability with Unknown Magnetic Field Topology

The stability of a shocked interface in magnetohydrodynamics (MHD) is investigated through linear stability analysis and two-dimensional simulations. The Richtmyer-Meshkov instability (RMI) occurs when a shock interacts with a rough surface and leads to the growth of a penetrating spike and fluid mixing. This process inhibits energy transport in inertial confinement experiments and is responsible for early mixing of heavy elements in supernova explosions. Numerical experiments and linear stability analysis demonstrated an applied magnetic field of sufficient strength aligned transverse or tangential to the shock front impedes vorticity generation at a fluid interface [1,2]. This study explores the evolution of a shocked interface in MHD without placing any assumptions on the topology of the magnetic field. Numerical studies performed with FLASH verify results discovered through linear stability analysis. A field that is tangent to the shock front minimizes vorticity generation at the interface due to field line tension, and all field orientations effectively suppress penetration and mixing that are characteristic of the RMI.

[1] Samtaney, R., Physics of Fluids 15, L53 (2003).

[2] Wheatley, V., Samtaney, R., Pullin, D., and Gehre, R., Physics of Fluids 26, 016102 (2014).