Sheath propagation along the cathode of a plasma opening switch

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