Published online by Cambridge University Press: 13 March 2009
The dispersion curves of mixing mode between electrostatic and electromagnetic waves propagating perpendicularly to the ambient magnetic field are computed for frequency range near the lower hybrid frequency in the case of a finite-β plasma with a Maxwellian velocity distribution. The detailed results apply to a hydrogen plasma. The result indicates that the lower hybrid frequency is neither the resonance frequency of the electromagnetic wave nor the cut-off frequency of the electrostatic wave. In a high-β plasma, the plateau of the dispersion curve disappears and the electrostatic approximation (Bernstein mode) is not valid up to the wavelength of the order of proton Larmor radius. The polarization is left-handed, and a trace of the most dominant intensity ratio of wave magnetic field energy to the electric field energy in each branch is given approximately by the cold-plasma dispersion curve.