Enhancement of Arc Ignition on Tungsten in Helium Plasmas with Impurity Gases

抄録

Arcing was ignited on deformed tungsten (W) surfaces, where W fuzz and/or nano-tendril bundles (NTBs) were grown, by steady state helium (He) plasma exposures with impurity gas seeding. At the same sample potential of −250 V, the presence of NTBs enhanced the frequency of arc ignition, whereas no arc ignition appeared on typical fuzz surfaces without NTBs. After a series of arc ignitions on a sample surface with NTBs, the aspect ratio of NTBs decreased, indicating that protruded NTBs with larger aspect ratio tend to trigger arcing easily.