YAG Laser Guided Discharge in Air at Pressures lower than 1kPa

Abstract

Experiments of the laser guided discharge in air below 1kPa were carried out by using YAG laser. The pressure of the air is set to be from 10 to 1kPa. The following results are obtained: The laser beam effectively guides the discharge at lower pressures as far as the discharge can appear. For given pressure and voltage, there is an optimum guide distance, which brings the most effective guide by the laser beam. Range of voltages for effective laser guidance becomes narrow as increasing of the air pressure. Minimum voltage for laser guided discharge is a function of a variable defined as (air pressure)×(discharge gap).This function behaves like the Paschen's law for a virtual gas with low electric insulation.