Examination of the Coupling Between Electrothermal and Rayleigh-Taylor Instabilities in Pulsed Power Driven Implosions

Fast magnetohydrodynamic (MHD) instabilities dominate over slower m = 0 and m = 1 mode instabilities in high energy density (HED) pulsed-power settings when implosion timescales are faster than the Alfvén wave propagating through a material. For example, the electrothermal instability (ETI) is caused by the temperature and density dependence of electrical resistivity and results in temperature striations early in the current pulse. It is believed that this instability seeds the magneto-Rayleigh-Taylor (MRT) instability, which is known to cause non-linear mixing in inertial fusion concepts (ICF). The present work analyzes theoretical linearized growth rates for both the ETI and MRT, examines the coupling between the instabilities, and compares the results to single-mode 2D resistive magnetohydrodynamic simulations of Z-scale pulsed power configurations using a radiation-hydrodynamics code, Ares.