Formation and Characterization of a Conical Section of a Spherically Imploding Plasma Liner*

Spherically imploding plasma liners1 are a proposed low-cost, reactor-relevant magneto-inertial-fusion (MIF) driver for compressing magnetized plasma targets to fusion conditions. The Plasma Liner Experiment–ALPHA (PLX-α aims to demonstrate the formation of subscale plasma liners via dozens of merging supersonic plasma jets (with initial ion density ~ 1016 cm-3, velocity ≈50 km/s, mass ~ 1 mg, and using various gas species). In the ongoing, first set of PLX-α experiments, we plan to merge six and seven plasma jets to form a conical section of a spherically imploding plasma liner in order to assess the shock heating (and associated Mach-number degradation) and uniformity of the liner upon jet merging and during further convergence, before proceeding to fully spherical liner-formation experiments (if warranted by the conical-liner results). In this talk, we will summarize experimental findings to date on characterizing plasma jets formed by the newly designed PLX-α guns and conical-plasma-liner formation with up to seven guns. Gated fast-framing-camera images from initial shakedown experiments suggest that shock formation between adjacent merging jets is consistent with oblique-shock formation as observed in earlier two- and three-jet merging experiments.2,3