High Coulomb transfer pseudo-spark switch

In realizing electro-magnetic launchers, one of key components is a switch that can transfer high energy to a load and also has a precise triggering capability. The pseudo-spark switch is a good candidate to such applications. Various designs of the pseudo-spark switch had been tested at different institutes for high-energy transfer, but not high enough to fulfill specifications of the launcher experiment. To adopt required specifications of the launcher that are 20 kV nominal hold-off voltage, 150 kA peak current, /spl sim/1 ms pulse-width, and /spl sim/ 1,000 shot lifetime, a pseudo-spark switch is designed and fabricated. A high dielectric surface discharge trigger unit is employed in the switch. Two different pseudo-spark switch geometries are fabricated and tested. One has hollow anode and hollow cathode with axially symmetric ring slit bore hole channels. Another has radial hollow anode and cathode with multi-channel bore holes. All electrodes are made of stainless steel. A maximum 100 kJ capacitor bank is used to test coulomb transfer capability of the switch. The 100 kJ capacitor bank is consisted of two parallel-connected 50 /spl mu/F, 45 kV capacitors. Helium and argon are used in the switch test at different pressure ranges.