Investigations of a radial multichannel pseudospark switch for currents higher than hundred kA

A radial multichannel pseudospark switch for currents of several hundred kA is under investigation. In this switch the current is distributed to several discharge channels which are arranged around one common hollow cathode. A parallel ignition of up to 12 discharge channels could be demonstrated. Investigation of the cathode spots reveal that only spots with low erosion appear even if increasing the current per channel above the threshold value of about 50 kA known from single channel switches. In the multichannel switch this low erosion mode is supported by the plasma movement due to magnetic forces. In lifetime tests of more than 200000 pulses with a peak current of 220 kA, a pulse duration of about 15 /spl mu/s and a repetition rate up to 2 Hz (200000 as total charge transfer) the erosion was shown to be less than 0.1 /spl mu/g/C, which is at least two orders of magnitude lower compared to conventional spark gaps.