Sheath propagation along the cathode of a plasma opening switch

A model is proposed for sheath propagation along the cathode of a plasma opening switch that is valid for switch conditions intermediate to the erosion-dominated and MHD-dominated regimes. The model assumes that the sheath propagates due to erosion of the plasma that conducts the current. The calculated velocity of propagation agrees with particle-in-cell simulation results much better than do velocities calculated by previous models that assumed magnetic pressure opens a vacuum gap along the cathode.