  This work numerically investigates the role of viscosity and resistivity on
Rayleigh-Taylor instabilities in magnetized high-energy-density (HED) plasmas
for a high Atwood number and high plasma beta regimes surveying across plasma
beta and magnetic Prandtl numbers. The numerical simulations are performed
using the visco-resistive magnetohydrodynamic (MHD) equations. Results
presented here show that the inclusion of self-consistent viscosity and
resistivity in the system drastically changes the growth of the Rayleigh-Taylor
instability (RTI) as well as modifies its internal structure at smaller scales.
It is seen here that the viscosity has a stabilizing effect on the RTI.
Moreover, the viscosity inhibits the development of small scale structures and
also modifies the morphology of the tip of the RTI spikes. On the other hand,
the resistivity reduces the magnetic field stabilization supporting the
development of small scale structures. The morphology of the RTI spikes is seen
to be unaffected by the presence of resistivity in the system. An additional
novelty of this work is in the disparate viscosity and resistivity profiles
that may exist in HED plasmas and their impact on RTI growth, morphology, and
the resulting turbulence spectra. Furthermore, this work shows that the
dynamics of the magnetic field is independent of viscosity and likewise the
resistivity does not affect the dissipation of enstrophy and kinetic energy. In
addition, power-law scalings of enstrophy, kinetic energy, and magnetic field
energy are provided in both injection range and inertial sub-range which could
be useful for understanding RTI induced turbulent mixing in HED laboratory and
astrophysical plasmas and could aid in the interpretation of observations of
RTI-induced turbulence spectra.
