Kinetic Alfvén waves in the presence of an inhomogeneous electric
field applied perpendicular to the ambient magnetic field in an anisotropic,
inhomogeneous magnetoplasma are investigated. The particle aspect approach
is adopted to investigate the trajectories of charged particles in the
electromagnetic field of a kinetic Alfvén wave. Expressions are found for the
field-aligned current, the perpendicular current, the dispersion relation and the
particle energies. The growth rate of the wave is obtained by an energy-
conservation method. It is predicted that plasma density inhomogeneity is the
main source of instability, and an enhancement of the growth rate by electric
field inhomogeneity and temperature anisotropy is found. The dispersion
relation and growth rate involve the finite-Larmor-radius effect, electron
inertia and the temperature anisotropy of the magnetoplasma. The applicability
of the investigation to the auroral acceleration region is discussed.