Effect of limiting the cathode surface on direct current microhollow cathode discharge in helium

TL;DR

This study demonstrates that limiting the cathode surface in microhollow cathode discharges enables parallel operation without individual ballasting by inducing an abnormal glow regime with increasing voltage.

Contribution

It introduces a method to operate multiple microdischarges in parallel by controlling cathode surface area, avoiding the need for individual ballast resistors.

Findings

Limiting cathode surface induces abnormal glow regime.

Parallel microdischarges can be lit without individual ballasts.

Voltage increases with current in the abnormal glow regime.

Abstract

This paper describes how to light several microdischarges in parallel without having to individually ballast each one. The V-I curve of a microhollow cathode discharge is characterized by a constant voltage in the normal glow regime because the plasma is able to spread over the cathode surface area to provide the additional secondary electrons needed. If one limits the cathode surface area, the V-I characteristic can be forced into an abnormal glow regime in which the operating voltage must increase with the current. It is then possible to light several microdischarges mounted in parallel without ballasting them individually.