Hybrid-kinetic stability properties of high-beta plasmas

Abstract

A hybrid-kinetic model (Vlasov ions and drift-kinetic electrons) is used to investigate the equilibrium and stability properties of collisionless linear screw-pinch configurations, assuming low-frequency perturbations (|ω|≲ωci) but making no a priori assumptions regarding the size of the ion Larmor radius (arbitrary rLi/L⊥). A general eigenvalue equation is derived for perturbations about a general equilibrium characterized by density profile N(r), isotropic ion equilibrium f0i(H), and locally Maxwellian electrons. This eigenvalue equation clearly exhibits the importance of finite electron temperature and electron kinetic effects parallel to the magnetic field direction, and reduces to the Vlasov-fluid eigenvalue equation of Freidberg in the limit of zero electron temperature.