A hybrid-kinetic model for high-β plasmas
Abstract
A hybrid-kinetic model (Vlasov ions and drift-kinetic electrons) is developed to describe the equilibrium and stability properties of collisionless high-beta plasmas in arbitrary magnetic field configurations. No ordering of ion properties (such as ω/Ωi and rLi/L⊥) is assumed, so the ions are described by the exact (unexpanded) Vlasov equation. The electrons are assumed to be strongly magnetized with ω/Ωɛ ∼rLe/L⊥=ɛ≪1, and the electron Vlasov equation is expanded in ɛ to give a drift-kinetic equation for fe. Examples of linear screw-pinch equilibria are constructed to demonstrate the ease with which equilibrium solutions are found within this formalism. Also, it is shown that the hybrid-kinetic model correct to O (ɛ) includes physical effects which are important during the implosion and immediate post-implosion phases of high-density pinch experiments, where stability behavior is characterized by the fast time scale ω-1LH= (ΩeΩi)-1/2. In particular, a local dispersion relation is derived for the modified-two-stream and lower-hybrid-drift instabilities, which have characteristic growth rates of order (ΩeΩi)1/2 when ω2pe/Ω2e≫1.
- Publication:
-
Physics of Fluids
- Pub Date:
- November 1975
- DOI:
- 10.1063/1.861048
- Bibcode:
- 1975PhFl...18.1507D
- Keywords:
-
- Collisionless Plasmas;
- Kinetic Equations;
- Magnetic Field Configurations;
- Magnetohydrodynamic Stability;
- Plasma Dynamics;
- Vlasov Equations;
- Distribution Functions;
- Drift Rate;
- Electromagnetic Fields;
- Mathematical Models;
- Maxwell-Boltzmann Density Function;
- Plasma Frequencies;
- Plasma Pinch;
- Time Dependence;
- Plasma Physics