Azimuthally symmetric unidirectional ion cyclotron wave exciter

A unidirectional device for excitation of azimuthally symmetric (m = 0) ion cyclotron waves is proposed. This work is related to the m = ± 1 traveling wave coupler which was described by Hipp, Kristiansen, and Hagler (Ref. 4). The m = 0 coupler is analyzed theoretically and numerical calculations are made of maximum loading resistance and directivities as functions of plasma density. Directivities of better than 0.99 are found.