A simulation of electron motion in the cathode sheath region of a glow discharge in argon

Abstract

Electron motion in the cathode sheath region of a glow discharge in argon has been simulated for a linearly decreasing electric field using a one-dimensional computer model. Distribution functions for the electron flux crossing the sheath have been calculated for 12 values of the cathode fall between 180 and 1400 V encompassing the normal and abnormal regimes. Macroscopic variables including the Townsend ionisation coefficient, the electron multiplication factor and the mean electron energy have been determined for cathode fall values between 180 and 1000 V. It is shown that the proportion of electron flux crossing the sheath without collisions increases as the cathode fall is raised. When the cathode fall is in the range 300-900 V, the electron flux at the sheath/negative-glow boundary is found to be highly directional with distinct beam-like characteristics. Beyond 900 V, the largest component in the distribution of electron flux to reach the boundary region is the collision-free group. These electrons enter the negative glow with energies corresponding to the cathode fall potential and are nearly mono-energetic. In this case, the entire cathode sheath/negative-glow region can be referred to as an 'electron-beam' glow discharge.

A self-consistent model for negative glow discharge lasers: the hollow cathode helium mercury laser

“…This distinct structure results from assuming that electrons emitted from the cathode have a monoenergetic distribution with a reduced energy of E , . If instead a distribution with a spread in energy of a few eV, such as that measured by Hagstrum [48] were used the distinct features in the flux spectrum would be smoother as seen in the results computed by Carman for the cathode sheath in an argon glow discharge [83]. Moreover if the energy of secondary electrons created by ionization in the sheath was not assumed to be zero but rather with a distribution defined by the differential cross section the distinct features in the high energy region of the spectrum would be further smoothed.…”

The use of hollow cathodes in deposition processes: A critical review

“…high energy [131], (b) there is enhanced electron emission from the cathode due to bombardment by photons and metastable atoms [23,31,118,[132][133][134].…”

Full‐dimensional Monte Carlo simulation of glow discharges with superposed magnetic fields

“…Other methods that also work for the non-equilibrium cathode fall region and are used for direct current as well as radio frequency discharges are the "convective scheme", [ll, 121, macroscopic approaches like beam-models [13] A special kind of MC model are "particle-in-cell" codes, which can be seen as selfconsistent MC models on a phase space grid where feedback occurs using Poisson's equation to recalculate the electric fields from the charge distribution after each step [lo].…”