Microarcing in a Helicon Plasma Reactor

Microarcing is investigated with a helicon plasma reactor in an argon plasma. A Langmuir probe was used to measure the floating potential during arc events, and a stainless-steel probe arm on which microarcs occurred was used to measure the associated current flow. The frequency of microarc events (MAEs) was analyzed with varying radio-frequency powers and gas pressures and was found to strongly depend on the floating potential. The microarcs were shown to cause a drop in the bulk floating potential that lasted on the order of hundreds of microseconds to milliseconds. During this period, a current on the order of an ampere was found to flow to the site of the MAE, leading to a total charge flow on the order of 10^-3 C .