Multiphase shock-turbulence interactions in decaying magnetohydrodynamic turbulence

ORAL

Abstract

Studies of shock-turbulence and shock-vortex interactions in sub- and super-Alfvénic magnetised turbulence have major importance in astrophysical plasma flows within the interstellar medium (ISM). Here we conduct high resolution implicit large eddy and direct numerical simulations of magnetohydrodynamic (MHD) turbulence with Lagrangian tracers to investigate the propagation of a cylindrical shock into an inhomogeneous, multiphase medium and study the turbulence and magnetic field amplification in the post-shock mixed region, replicating a similar shock tube experiment being performed at the National Ignition Facility (NIF) of the Lawrence Livermore National Laboratory (LLNL). Simplified theoretical models based on curved shock induced vorticity and Favre-averaged MHD Rankine-Hugoniot relations are used to predict the post-shock Reynolds stress and velocity dispersion, which varies nearly linearly with the average Atwood number in the inhomogenous medium, consistent with the impulsive model for the growth rate of Richtmyer-Meshkov instabilities (RMI) forming in the outer extent of the turbulent, shocked gas. Furthermore, the long-time behaviour of the decay of shock-driven turbulence is also briefly explored.

*We acknowledge the NIF Discovery Science Program for allocating upcoming facility time on the NIF Laser to test aspects of the models and simulations discussed. J.K.J.H. acknowledges funding via the ANU Chancellor's International Scholarship. C.F. acknowledges funding provided by the Australian Research Council (Future Fellowship FT180100495 and Discovery Projects DP230102280), and the Australia-Germany Joint Research Cooperation Scheme (UA-DAAD). We further acknowledge high-performance computing resources provided by the Leibniz Rechenzentrum and the Gauss Centre for Supercomputing (grants pr32lo, pr48pi and GCS Large-scale project 10391), the Australian National Computational Infrastructure (grant ek9) and the Pawsey Supercomputing Centre (grant pawsey0810) in the frame- work of the National Computational Merit Allocation Scheme and the ANU Merit Allocation Scheme.

Publication: Turbulence generation behind an inhomogeneous, curved shock in decaying magnetohydrodynamic turbulence (under planned papers)

Presenters

  • Justin Kin Jun Hew

    • Australian National University

Authors

  • Justin Kin Jun Hew

    • Australian National University
  • Christoph Federrath

    • Australian National University
  • Seth Davidovits

    • Lawrence Livermore Natl Lab