Electron-electron scattering in a quasi-neutral particle simulation code for ECR plasma processing devices
- Naval Research Lab., Washington, DC (United States). Plasma Physics Div.
The authors have recently developed an axisymmetric quasi-neutral particle simulation code to study heating and transport of plasma in an ECR reactor configuration in which the electrons are always strongly magnetized, but the degree of magnetization of the ions varies spatially. for this system with pressures on the order of a few milliTorr, the plasma is considered to be weakly collisional, with mean free paths on the order of a few centimeters. Electrons may collide with the neutral gas in various states, and with each other. Electron-electron (e-e) collisions are especially important since these collisions are responsible for forming the tail of the electron distribution function and for redistributing the energy toward a Maxwellian. The energy distribution is determined by a competition between e-e collisions, which tend to Maxwellianize the distribution, and inelastic electron-atom collisions, which deplete the high energy tail. Therefore it is important to use the right rate coefficients to represent e-e collisions. In plasmas, electrons collide mainly through multiple shielded small angle scattering and should be described by a Fokker-Planck collision formulation. For particle simulations, Fokker-Planck collisions may be cast in the form of a grid based force in the form of the Langevin equation. The authors have implemented a more exact Langevin equation based on diffusion and drag coefficients appropriate for electrons in a plasma.
- OSTI ID:
- 428038
- Report Number(s):
- CONF-960634-; TRN: IM9708%%367
- Resource Relation:
- Conference: 1996 IEEE international conference on plasma science, Boston, MA (United States), 3-5 Jun 1996; Other Information: PBD: 1996; Related Information: Is Part Of IEEE conference record -- Abstracts: 1996 IEEE international conference on plasma science; PB: 324 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Invalidity of local thermodynamic equilibrium for electrons in the solar transition region. I. Fokker-Planck results
Kinetic modeling of electron transport in C-Mod and DIII-D tokamaks