Influence of electrode characteristics on DC point-to-plane breakdown in high-pressure gaseous and supercritical carbon dioxide

Discharges in supercritical conditions is a new field in plasma science. The supercritical phase has distinctive properties that may allow for unique plasma processing applications. In this paper, we study plasma generation in a point-to-plane geometry in the micrometer scale. The effects of needle characteristics, including tip diameter and plane electrode surface roughness, on discharge initiation are studied. The influence of pressure, temperature, and fluid density on breakdown voltage and reduced breakdown electric field are also investigated. Index Terms--Breakdown, carbon dioxide, microplasma, supercritical fluid (SCF).