The velocity distribution f(v) of the electron component of a weakly ionized plasma is investigated in a spatially homogeneous external electric field E. Both static and time-dependent E are considered. The time evolution of f is described by a Boltzmann equation in which the ions and neutral particles are assumed to have a Maxwellian distribution with a priori specified temperatures while the electron-electron interactions are given by a Landau-type collision integral. The (approximate) solution scheme used to solve this equation for a stationary f (in a constant field) is found to have nonunique solutions for certain ranges of E, in agreement with that found in earlier investigations using a different method of solution. These results are interpreted to correspond to hysteresis effects when the field is changing very slowly: with the true stable solution undergoing a very sharp changeover, possibly a discontinuous transition, at a certain critical E. This can be understood intuitively as a transition in the stationary state of the electrons from a low-energy regime dominated by strong coupling to the ions to a high-energy regime dominated by electron-electron and electron-neutral collisions.
All Science Journal Classification (ASJC) codes
- Computational Mechanics
- Condensed Matter Physics
- Mechanics of Materials
- Physics and Astronomy(all)
- Fluid Flow and Transfer Processes