Numerical study of three-dimensional instability development in solid liner dynamic screw pinches *

Magnetically driven liner implosions experience magneto-Rayleigh-Taylor instabilities (MRTI) which act to reduce liner integrity and thus fusion fuel compression and confinement in magneto-inertial fusion (MIF) experiments. As such, mitigating MRTI is important for the advancement of MIF concepts such as Magnetized Liner Inertial Fusion (MagLIF). Dynamic screw pinches (DSP) leverage magnetic field line tension to stabilize MRTI by employing an initially helical magnetic field to drive the implosion. The field polarization at the liner surface rotates during the implosion, distributing the stabilizing benefits of field-line tension across a larger portion of the MRTI mode spectrum. Although linear theory predicts significant reduction in cumulative MRTI growth compared to conventional z-pinch implosions, detailed numerical exploration of MRTI development in DSP is needed. We present results from three-dimensional magnetohydrodynamic simulations exploring MRTI reduction for a variety of DSP implosions. Accounting for physical effects such as nonlinear instability development, magnetic diffusion, shock dynamics, and material heating, the modeling we present provides a crucial advance in the DSP concept for use in liner implosion experiments, including potential MagLIF-like MIF experiments.