Nonlocal theory of beam-driven electron Bernstein waves

A nonlocal theory of electron Bernstein waves driven unstable by an axial beam (V = V/sub b/z) of finite width has been developed. Assuming a parabolic density profile for the background plasma, an equation describing the mode structure of the wave is obtained in the slab geometry. The eigenfunctions are found to be Hermite polynomials. Expressions for the growth rates of the instabilities caused by Cerenkov and slow cyclotron interactions are derived. The results of the theory are applied to explain some of the experimental observations of Jain and Christiansen [Phys. Lett. A 82, 127 (1981)]