Plasma Erosion Opening Switch Development at Nrl

Plasma Erosion Opening Switch (PEOS) experiments are described covering a conduction time range from 35 ns on Gamhle I to 2300 ns on Pawn. A microwave interferometer is used to estimate the plasma density for some of the experimental cases. The conduction current, conduction time, geometrical configuration and density are used to calculate the plasma center-of-mass displacement from JxB forces and to compare the conduction current with the bipolar limit of PEOS theory. At short conduction times, the conduction current agrees with the bipolar limit. As the conduction time increases, the conduction current is orders-of-magnitude less than the bipolar value, possibly the result of plasma displacement and/or compression by JxB forces. Eventually, the PEOS does not open: instead, the cmTent is convected toward the load as in a plasma flow switch. The transition to conduction current much less than bipolar occurs when the center-of-mass displacement is a significant fraction of the plasma length.