Cold-cathode high-power thyratron for high-Coulomb switching applications

Industrial pulsed power applications like magnetoforming, concrete recycling and rock fracturing require high-current switches for the power conditioning system which are not yet available with sufficient lifetime and reliability. In particular, the simultaneous handling of pulse currents of the order of 100 kA in amplitude and tens of microseconds duration, at a voltage approaching 20 kV or more, is not yet possible with a standard product at a reasonable lifetime on the order of hundreds of kilo-Coulombs. Investigation into a cold-cathode gas discharge switch is presented, which promises high-coulomb transfer switching capability at high peak current and long lifetime. It is based on an axial magnetic field superimposed to a conventional pseudospark discharge; the low-pressure switching arc diffuses to a diameter up to 40 mm at currents above 30 kA, whereas the arc column tends to constrict to a diameter on the order of 5 mm without the application of an axial magnetic field