ePLAS modeling of plasma JETS

Summary form only given. The implicit simulation code ePLAS has been applied to plasma jets generated by mini-rail guns, as currently under development by HyperV Corporation for plasma production and compression aimed at use with PLX. Rails for the guns are typically planar, 2.5 cm apart and arranged to transport an initial 1 cm or wider vertical plasma band for some 10 cm into a void. The driving magnetic field is 3.2 T. Typical starting plasmas are singly ionized argon at an initial electron density of 1017 cm"3. Discussion will be given to effects from variations in these parameters. The emphasis is on the production of a single jet, but we include initial results for the merger of jet pairs. Here, ePLAS is implemented, in both its traditional implicit/hybrid form1 where it is restricted by an electron Courant time step, and in a new super-hybrid form that extracts the main electron moments from the Eand 5-field solutions, providing numerical stability at ion Courant limits, for at least a 10 times larger time step. Thus, the code can probe microsecond jet dynamics with computational economy. We look at jet transport into the void beyond the gun, and gun end current reconnection effects. We examine possible field penetration at the cathode and anode gun electrodes. Cathode erosion and EMHD B-field penetration are possible at lower jet densities2. Emission and drag effects at the gun walls will be discussed, as will ionization influences in the jet body, manifest through the use of either Thomas-Fermi analytic or SESAME tabular equations of state models in the code. The benefits of alternate fluid and particle treatments for the plasma ions will be compared. Particle modeling simplifies the tracking of modified ionization states, and inter-beam collisions. We will also discuss preliminary results for effects from the presence a background neutral gas modeled as a third species.