The combined kinetic effects of the ion temperature gradient and the velocity shear of a plasma flow parallel to the magnetic field on the drift-Alfven instabilities

Abstract

The drift-Alfvén instabilities of the sheared flow along the magnetic field of a finite beta (1>β≫me/mi) plasma with comparable inhomogeneous ion temperature and homogeneous electron temperature are examined by the numerical analysis of the derived linear dispersion equation. Accounting for the electromagnetic ion kinetic response, which has been neglected in conventional discussions of the drift-Alfvén instabilities of a steady plasma, a new kinetic drift-Alfvén instability has been found. It develops in a plasma shear flow due to the coupled action of the ion temperature gradient, the flow velocity shear, and the inverse ion Landau damping.

Dispersion relation and instability for an anisotropic nonuniform flowing plasma

“…The plasma instability can be directly evaluated using equations ( 16) and ( 22)- (38), where the coefficients demonstrate that the nonuniformity is the critical parameter of the instability. The validity of the formalism has been confirmed by comparing the explicit dispersion relation (25) and the implicit dispersion relation (1). It is demonstrated that the formalism can be used to develop the instability diagram and the instability criterion for a nonuniform plasma.…”

“…The imaginary frequency ω i can be directly evaluated by using equation (25), where ω r and k are obtained using equation (24).…”

“…By analyzing the Vlasov equation, the effects of nonuniform flow and temperature on wave properties have been studied for a specific plasma flow, wave mode, and frequency regime [22][23][24][25]. On the other hand, a generalized dielectric tensor and a dispersion relation have been derived for plasmas with nonuniform densities, time-varying flows, and anisotropic temperatures [8,26].…”