Whistler anisotropy instability with a cold electron component: Linear theory
Abstract
The whistler anisotropy instability is driven by an electron temperature anisotropy T⊥/T∥ > 1 where ⊥ and ∥ denote directions perpendicular and parallel, respectively, to the background magnetic field Bo. Here kinetic linear theory in a magnetized, homogeneous, collisionless plasma model is used to study this instability when the electron velocity distribution may be represented as the sum of a hot, anisotropic bi‐Maxwellian and a cold, isotropic component. The critical β∥e, the value at which the maximum growth rate of the instability changes from propagation parallel to Bo to oblique propagation, decreases with increasing nc/ne, where nc is the cold electron density and ne is the total electron density. At parallel propagation the maximum growth rate increases with nc/ne up to nc/ne ≃ 0.8, but then diminishes with further increases of the relative cold electron density. Introduction of a cold electron component can reduce the hot electron anisotropy necessary to excite this instability by up to a factor of 2.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 01, 2012
- Source ID
- 10.1029/2012ja017631
Entities
People
- Kaijun Liu
- Richard E Denton
- S. Peter Gary
- Shuo Wu
Organizations
- Defense Threat Reduction Agency