MHD Instabilities in Non-Equilibrium Z-Pinch Driven by a Multi-Megaampere Current

Summary form only given. Magnetohydrodynamic (MHD) instabilities play a critical role in a number of pulsed power experiments in which multi-megaampere currents melt solid conductor surfaces and turn them into hot plasmas in a matter of microseconds or less. Complex motions that these plasmas exhibit lead to the development and growth of violent MHD instabilities that have the potential of disrupting the currents flowing through the conducting material or of introducing conductor material into locations where such material is not desired. The accelerated boundary of a non-equilibrium Z-pinch driven by a multi-megaampere current exhibits both curvature-driven m=0 (sausage) and Rayleigh-Taylor instabilities. The interplay between these instabilities and the effect it may have on the dynamics of the Z-pinch is studied through a number of 2-D magnetohydrodynamic simulations performed with the state-of-the-art MHD code MHRDR. An important challenge for modeling is to predict the maximum magnetic field on the pinch surface that can be obtained prior to current disruption. The results of this study can be generalized to the more complicated problem of modeling a moving liner driven by a megaampere current.