Dynamic Characteristics of a Microhollow Cathode Sustained Discharge with Split Third Electrodes for Potential Flow Application to Flow Velocimetry

The dynamic behavior of a microhollow cathode sustained discharge with split third electrodes is experimentally investigated. The sustained discharge swells isotropically in the presence of a small amount of argon gas flow that is not clearly detectable with a conventional single third electrode. At high flow rates, the sustained discharge transitions to a fast-moving constricted discharge with an arc shape. The modified discharge structure causes a shift in current distribution over the third electrodes, and the current peak location varies linearly with the flow rate over a certain flow range. Such linear behavior may be applied to in situ flow velocity measurement.