Numerical study of a plasma opening switch conduction phase

Abstract

Dynamics of a Plasma Opening Switch (POS) during a conduction phase is numerically studied within the frame of a two-dimensional two-fluid system of magnetohydrodynamic (MHD) equations. The initial conditions for simulations are chosen to ensure the fast magnetic field propagation to a load plasma edge near the cathode. Simulations demonstrate that the POS dynamics depends on two plasma parameters: number of ions near the cathode and electron Hall parameter. It is shown that with respect to these parameters one of the three following regimes of POS operation can occur: dominant Hall effect, dominant MHD effects, and intermediate regime with equal influence of Hall and MHD effects. Two sets of simulations are carried out to derive the numerical scalings for conduction current and for conduction time of each of these regimes. The numerical scalings correlate with scalings proposed for the HAWK generator.