Kinetic Alfven waves in an inhomogeneous anisotropic magnetoplasma in the presence of an inhomogeneous electric field: particle aspect analysis

Kinetic Alfven waves in the presence of an inhomogeneous electric field app lied perpendicular to the ambient magnetic field in an anisotropic, inhomog eneous magnetoplasma are investigated. The particle aspect approach is adop ted to investigate the trajectories of charged particles in the electromagn etic field of a kinetic Alfven wave. Expressions are found for the field-al igned current, the perpendicular current, the dispersion relation and the p article energies. The growth rate of the wave is obtained by an energy-cons ervation method. It is predicted that plasma density inhomogeneity is the m ain source of instability, and an enhancement of the growth rate by electri c field inhomogeneity and temperature anisotropy is found. The dispersion r elation and growth rate involve the finite-Larmor-radius effect, electron i nertia and the temperature anisotropy of the magnetoplasma. The applicabili ty of the investigation to the auroral acceleration region is discussed.