Similarity Relations for Low Pressure Glow Discharges in Noble Gases

A simple three level atomic model that includes excitation, ionization, stepwise ionization, and diffusion is used to determine similarity relations for low pressure noble gas discharges. A two-temperature electron energy distribution is also included in the model. Similarity relations involving the reduced electric field, the electron main body temperature, the electron tail temperature, and the pressure-radius product are developed. It is found that the reduced electric field and the electron tail temperature depend on the discharge current as well as the pressure radius product. Good agreement as well as the pressure-radius product. Good agreement is obtained between the similarity relation predictions and experimental results in helium and neon discharges.