IOP Groups

Switches

The most recent plasma switch to be developed is based on a pseudospark discharge. The pseudospark discharge is a fast low-pressure gas discharge which occurs in a special hollow cathode geometry. The background gas pressure is such that pd, the product of the gas pressure p and the distance d between the front faces of the cathode and anode, is between the Paschen minimum and vacuum breakdown. Its geometry consists of two or more plane-parallel electrodes with a circular hole each separated by insulating rings at a distance of typically several millimetres, and an enclosed cavity behind the cathode hole. A triggered pseudospark discharge is used for high current switching applications because of its high current rise rate, 100% current reversal, long lifetime and precise and effective high-repetition rate operation (> 100 kHz). The homogeneous high-density discharge plasma in a pseudospark, is different from arcs existing in conventional high-current switches such as vacuum arc switches or spark gaps, and is the key reason for its unique switching properties.

For more information see:

Pseudosparks

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