Investigations of Discharge Sustenance in a Dielectric Barrier-Based Microhollow Cathode

In this work, a microhollow cathode variant consisting of cylindrical cathode structure and a coaxial anode, with a layer of dielectric barrier on the inner wall of the cathode cavity, has been investigated. This arrangement allows the device to be operated at atmospheric pressure reaching electron densities up to 1018 m-3 in the microhollow cathode cavity. The discharge initiates from the narrow gap region between the cathode and the anode, followed by hollow cathode discharge. The presence of the anode in the discharge cavity causes the discharge electrons to be absorbed by the anode. A theoretical approach has been followed and it establishes a criterion for sustenance of this discharge in the microhollow cathode cavity. This criterion resulted from the fact that for discharge to be sustained in the hollow cathode cavity, the generation of electrons should be balanced by the absorption of electrons. Both these phenomena have been quantitatively explained by electron multiplication quotient and a multipass parameter for hollow cathode discharge has been evaluated.