A Folded Waveguide Coupler for Plasma Heating in the Ion Cyclotron Range of Frequencies

A new type of waveguide coupler for plasma heating experiments in the ion cyclotron range of frequencies (ICRF) is introduced. The coupler consists of a series of interleaved metallic vanes within a rectangular enclosure analogous to a very wide simple rectangular waveguide that has been "folded" several times. At the mouth of the coupler a plate is attached which contains coupling apertures in each "fold" or every other "fold" depending upon the application. This plate serves primarily as a wave field polarizer that converts coupler fields to the polarization of the fast magnetosonic wave within a plasma. Theoretical estimates indicate that the folded waveguide coupler is capable of high-efficiency multimegawatt operation into a plasma.