Excitation of ion Bernstein waves from loop antennas

Direct excitation and propagation of ion Bernstein waves from low-impedance current-carrying loop antennas in the ion cyclotron frequency range are studied over a range of plasma and antenna parameters. The dependence of wave coupling efficiency on plasma density and on wave frequency and parallel wavelength is obtained from measurements of wave amplitude and variations in antenna impedance. Comparisons are made to a simple nonuniform warm-plasma model of the coupling problem. Generally good agreement is found between theory and experiment. As a result, some guidelines are proposed concerning antenna design.