Power Flow Effects of the Applied Axial Magnetic Field on Maglif Experiments at the Z Machine

Abstract

The Z machine is a pulsed power generator capable of producing >20 MA current pulses and is used in a variety of HEDP experiments including x-ray production, materials science, and fusion energy [1] . A challenge, faced particularly by the Magnetized Liner Inertial Fusion (MagLIF) experiments, is that multi-MA current losses are routinely observed [2] . Current loss attributed to plasma formation in the double post-hole convolute has been a previous focus of inquiry [3] , though recent developments of velocimetry-based current diagnostics have enabled current measurements closer to the load [4] . This diagnostic capability enables the study of loss mechanisms interior to the convolute, where MagLIF’s applied axial magnetic field intersects with the final transmission line. Since the inner transmission lines on Z are insulated by the self-magnetic field generated from the current pulse, changes to the field topology could significantly increase shunted current. We explore the hypothesis that the applied axial magnetic field interferes with magnetic insulation and drives current to shunt prior to the experimental load. Analytical calculations, 2D fluid simulations, and experimental measurements will be presented.