Numerical studies on charged particle behavior in a cathode sheath of normal and abnormal glow dc discharge

The charged-particle energy distribution and scattering angular distribution for helium normal and abnormal dc glow discharge in the cathode sheath region are studied by Monte Carlo simulation (MCS). Some types of collisions (elastic, excitation, and ionization collision for electrons, elastic and charge-exchange collision for ions) are considered. The charged-particle free-flying time between collisions is determined by the charged-particle-neutral-gas collision frequency. The electron and ion energy distribution function, and the scattering angular distribution are calculated in this paper. The electron mean energy and mean drift velocity are also investigated. The results indicate that high-energy electrons exist in the cathode region, and the electron beam behavior is obtained for two kinds of discharges. Results are in good agreement with experiment.