A staged pre-ionization approach for Field-Reversed Configuration formation on MSX-II

The density, temperature, flux retention, and stability of an equilibrium Field-Reversed Configuration (FRC) strongly depend on the parameters of the pre-ionized plasma prior to field-reversal. Pre-ionization studies on the new MSX-II experiment at Los Alamos National Laboratory are investigating the impact of the pre-reversal plasma density, purity, and uniformity on the FRC parameters after reversal. The first pre-ionization studies use a staged process, first firing an annular array of coaxial rail guns to inject a weakly ionized gas, followed by an inductively coupled ringing multipole to achieve full ionization. Results are compared to those of the MSX-I experiment, which used the same annular array of coaxial rail guns but followed with a ringing-theta method to achieve full ionization.



*This work is supported by the U.S. Department of Energy, National Nuclear Security Administration. Approved for public release, LA-UR-22-26147.