A temperature-anisotropy instability for electromagnetic waves propagating across a static magnetic field

Abstract

The instability of electromagnetic waves propagating across a static magnetic field in the presence of a thermal anisotropy (T∥ > T⊥) is investigated. The marginal stabifity criterion as well as the rate of growth of the instability are derived. When compared with the fire hose instability (of electromagnetic waves propagating along the static magnetic field) it is found that higher electron pressures are required for this new instability to be set up; however, the maximal rate of growth is much larger than in the fire hose case.The interplanetary plasma is stable to this thermal anisotropy instability; high β plasma devices may be unstable.The T⊥ = 0 case treated by Hamasaki is recovered.