Low-pressure discharge in a trigger unit of pseudospark switch

The paper deals with the investigations of the discharge in the trigger unit of the pseudospark switch. The main attention is payed to study of the low-current auxiliary glow discharge, which is sustained in the steady-state mode before triggering, and to rearrangement of this discharge when the trigger pulse is applied to the trigger unit. The hydrogen pressure is varied through a range from 0.08 to 0.25Torr and the auxiliary discharge current in the electrode system with hollow cathode and hollow anode is up to 40mA. The estimates for the plasma density in the cathode cavity are provided. Under the action of the trigger pulse, the breakdown between the trigger electrodes occurs and the pulsed breakdown current is intercepted to the main cathode cavity of the switch. It is demonstrated that the process of the current interception strongly depends on the regime of sustaining the auxiliary discharge and on the fact, whether the potential electrode of the auxiliary discharge plays a role of the hollow cathode or the hollow anode.