Enhancement in the electromagnetic beam-plasma instability due to ion streaming
Abstract
We investigate the Weibel instability in counter-propagating electron-ion plasmas with focus on the ion contribution, considering a realistic mass ratio. A generalized dispersion relation is derived from the relativistic theory by assuming an initially anisotropic temperature, which is represented by a waterbag distribution in momentum space, which shows an enhanced growth rate due to ion response. Two-dimensional particle-in-cell simulations support the theoretical analysis, showing a further amplification of magnetic field on ion time scale. The effect of an initial anisotropic temperature is investigated showing that the growth rate is monotonously decreased if the transverse spread is increased. Nevertheless, the presence of ions generates that the instability can develop for significantly higher electron temperatures. Suppression of oblique mode is also explored by introducing a parallel velocity spread.
- Publication:
-
Journal of Plasma Physics
- Pub Date:
- April 2012
- DOI:
- 10.1017/S0022377811000559
- Bibcode:
- 2012JPlPh..78..181S