MAGNETIC FIELD DYNAMICS IN PLASMA OPENING SWITCH

Abstract

Computer simulations for magnetic field penetration into plasma of plasma opening switch (POS), and current loop formation in it are presented for various initial plasma densities, currents, and POS geometries. It is shown that the current loop dynamics in the POS is determined by the fast magnetic field penetration in plasma due to the Hall effect. The strong dependence of the current loop longitudinal velocity on the transverse coordinate, together with the influence of the boundary conditions at the POS cathode and anode, lead to the formation of the narrow S-shaped current loop even in a homogeneous plasma. It is shown that the control parameters influencing the dynam-ics of the magnetic field and the motion of the current loop in the POS are the initial plasma density, driving current and cathode radius. The POS resistance is calculated for wide range of initial plasma densities, currents, and cath-ode radiuses. It is shown, that POS resistance is proportional to the total current, inversely proportional to plasma density, and is in the range 10-3…1 Ω for plasma densities 1012…1015 cm-3.