Plasma Formation on the Surface of mm-Diameter Aluminum Rods by Pulsed Megagauss Magnetic Field

Megagauss magnetic field is pulsed on millimeter-diameter aluminum rods resulting in heating inside the skin depth, and plasma formation in a thinner layer at the surface.~ Driven by the University of Nevada, Reno-Nevada Terawatt Facility's (UNR-NTF) 2TW Zebra Z-pinch, 1.0 MA is delivered to the load, rising to current maximum in $\sim $100ns.~~ The load radius is chosen to be larger than the skin depth, placing the experiment in the 'thick wire' regime.~ In contrast to a thin uniform-current- density exploding wire, a thick wire exhibits plasma and magnetic pressure balance during current rise.~ Free expansion is limited, resulting in~high energy density and temperature.~ ~ The experiment is designed to limit large scale instability growth until after peak field. ~ During current rise, dynamic equilibrium is achieved for some 10's of nanoseconds and quasi-stable aluminum plasma heated to over 10 eV is held between a 3-5 megagauss magnetic field and a cool, dense, liquid aluminum wall.~ Preliminary understanding of the evolution of the rod interior and surface plasma is detailed with both experimental and computational results.~ Plans for future experiments, including new load designs and diagnostics under development, are given.