Studies of cylindrical liner Z-pinches at 1 MA on COBRA

Abstract

As part of the work on the Magnetized Liner Inertial Fusion (MagLIF) concept1, Awe et al. found on the 20 MA Z-machine that applying an externally generated axial magnetic field to a liner produces a helical striation pattern in the liner2. We are investigating this phenomenon using 10 mm long cylindrical metal liners having 4 mm diameter and varying wall thickness on the 1 MA, 100–230 ns COBRA pulsed power generator at Cornell University. In addition, we will present experimental results on a configuration that includes a wire initially connecting the cathode and anode on the axis of a cylindrical liner that does not initially connect the cathode to the anode. Results of these experiments both with and without external magnetic fields will be shown. Extreme ultraviolet (XUV) imaging as well as optical streak and 12 frame camera imaging are used to observe and analyze liner surface emission. Axial and side-on interferometry are used to determine the distribution of plasma both near the liner surface and inside the liner, assessing, among other things, the impact of non-uniformities during the plasma ablation phase of the experiments.