Parallel Energy Analysis of a Pure Electron Plasma with a Drifting Maxwellian Distribution

A theoretical equation to determine the number of escaping electrons with respect to the barrier voltage in a pure electron plasma with a drifting Maxwellian velocity distribution confined in a Malmberg-Penning trap is derived. Our derived model can accurately determine the temperature and drift energy of the pure electron plasma with such a velocity distribution. The escaping electron distributions can be experimentally obtained using the conventional parallel energy analysis developed by Eggleston et al. In preliminary experiments, pure electron plasma with a finite peak energy was generated using an electron beam emitted from a thermionic electron gun. The escaping electron distribution in the electron plasma based on the energy analysis corresponds to the derived model in the case that the energy of the electrons emitted from the gun is varied within the range of -10 to -30 V. Furthermore, through molecular dynamics simulations, we observed the relaxation process of an electron plasma from a drifting to nondrifting Maxwellian distribution. In this process, our model accurately described the drift energy and temperature. These parameters prove to be highly valuable for studying relaxation processes in terms of the energy transition from longitudinal to radial directions.