We report an experimental investigation of the light irradiation effect on the Townsend breakdown mechanism of plasma discharges in helium, at 5.2 K, for densities up to 23 mol l-1. The plasma discharges were generated in a pin-to-plane electrode geometry, separated by a gap distance of 5 μm. The pin electrode was the cathode. Two light sources, with wavelengths of 365 and 635 nm, were used. The influence of the pressure and the light flux was studied. Based on the results, a phenomenological interpretation of the effect of light irradiation on the breakdown mechanism is proposed. Photon-enhanced field emission of electrons could be of significant importance.
ASJC Scopus subject areas
- Condensed Matter Physics