Simulations of electron/electron instabilities: Electromagnetic fluctuations
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
- Laboratory for Plasma Astrophysics, Toyama University, Toyama 930, (Japan)
Electron/electron instabilities arise in collisionless plasmas when the electron velocity distribution consists of two distinct components with a sufficiently large relative drift speed between them. If the less dense beam component is not too tenuous and sufficiently fast, the electron/electron beam instability is excited over a relatively broad range of frequencies. This instability is often studied in the electrostatic limit, which is appropriate at {omega}{sub e}/|{omega}{sub e}|>>1, where {omega}{sub e} is the electron plasma frequency and {omega}{sub e} is the electron cyclotron frequency, but is not necessarily valid at {omega}{sub e}/|{omega}{sub e}|{approx}1. Here linear Vlasov dispersion theory has been used and fully electromagnetic particle-in-cell simulations have been run in a spatially homogeneous, magnetized plasma model at {beta}{sub e}<<1 and 0.5 {<=}{omega}{sub e}/|{omega}{sub e}|{<=}4.0. Theory and simulations (run to times of order 100{omega}{sub e}{sup -1}) of the electron/electron beam instability show the growth of appreciable magnetic fluctuations at {omega}{sub e}/|{omega}{sub e}|<2; these waves bear right-hand elliptical magnetic polarization. The simulations reproduce the well-known slowing and heating of the beam; at {omega}{sub e}/|{omega}{sub e}|<1 this heating is predominantly parallel to the background magnetic field, but as {omega}{sub e}/|{omega}{sub e}| becomes greater than unity the perpendicular heating of the beam increases. The simulations also demonstrate that, for {omega}{sub e}/|{omega}{sub e}|{approx}1, electromagnetic fluctuations impart to the more dense electron core component significant heating perpendicular to the background magnetic field. (c) 2000 American Institute of Physics.
- OSTI ID:
- 20215187
- Journal Information:
- Physics of Plasmas, Vol. 7, Issue 2; Other Information: PBD: Feb 2000; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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