The PLX-$\alpha$ Project: Progress and Plans

The Plasma Liner Experiment-ALPHA (PLX-$\alpha$) project aims to demonstrate the viability of spherically imploding plasma liners as a standoff driver for plasma-jet-driven magneto-inertial fusion (PJMIF) [Hsu et al., IEEE Trans. Plasma Sci.~{\bf 40}, 1287 (2012)]. In the past year, progress has been made in designing and testing new contoured-gap coaxial guns, 3D model development and simulations (via Eulerian and Lagrangian hydrocodes) of PLX-$\alpha$-relevant plasma-liner formation/implosion via up to 60 plasma jets ($\sim 100$~kJ of liner kinetic energy), 1D semi-analytic and numerical modeling of reactor-scale PJMIF (10s of MJ of liner kinetic energy), and preparation/upgrade of the PLX facility/diagnostics. The design goal for the coaxial guns is to form plasma jets of up to initial $n \sim 2\times 10^{16}$~cm$^{-3}$, mass $\approx 5$~mg, $V_{jet}\approx 50$~km/s, $r_{jet}=4$~cm, and length $\approx 10$~cm. The modeling research is assessing ram-pressure amplification and Mach-number degradation during liner convergence, evolution of liner non-uniformity amplitude and mode number, and exploration of PJMIF configurations with promising 1D and 2D fusion gains. Conical multi-jet-merging and full-4$\pi$ experiments will commence in Fall, 2016 and late 2017, respectively.