Asymptotic solution of lower-hybrid wave propagation in two-dimensional inhomogeneous plasma

An asymptotic expansion for the electrostatic potential in cold plasma due to excitation near the lower-hybrid frequency is developed which is valid in the presence of two-dimensional field and density inhomogeneities. The lowest-order terms of the expansion yield the resonance cone surfaces and WKB amplification factors associated with finite-sized sources. The technique is applied to investigate phased waveguide array excitation.