Resonant laser diagnostics of a planar plasma opening switch

The plasma opening switch (POS) is an integral part of inductive store pulsed power systems. Using flashboards coated with BaO and a dye laser tuned to the 493.4 nm ground state transition of the singly-ionized barium ion, resonant laser diagnostics have been employed to image the switch plasma and provide a measurement of the plasma density during conduction and opening. Gaps open during the conduction phase with their position in the inter-electrode region depending upon the initial fill plasma. There is little axial motion of the plasma, contrary to the predictions of analytical hydro model calculations performed using the measured switch parameters. This discrepancy may be due to a finite lifetime for ions in the switch that is less than the conduction time resulting in a larger effective mass. From a functional point of view modified bipolar model calculations best fit the data