Kinetic Alfven wave with loss-cone distribution function in the presence of beam velocities in an inhomogeneous magnetosphere

Abstract

Kinetic Alfven waves in the presence of an inhomogeneous electric field applied perpendicular to the ambient magnetic field with loss-cone distribution function and ion and electron beam are investigated. The particle aspect approach is adopted to investigate the trajectories of charged particles in the electromagnetic field of a kinetic Alfven wave. Expressions are found for the field-aligned current, the perpendicular current and the dispersion relation. The growth/damping rate of the wave is obtained by an energy conservation method. The effect of electron and ion beam, steepness of loss-cone and inhomogeneity of electric field are discussed. The plasma under consideration is assumed to be anisotropic and with low-b. The results are interpreted for the space plasma parameter appropriate to the auroral acceleration region of the earth’s magnetosphere.