Low Frequency Rf Heating with a Helical Coupler in a Hot Electron Plasma

A magnetic mirror (mirror ratio 2.38:1) containing ECRH generated hydrogen plasma, with a density of 5 x 1010 cm-3 with cold electron temperature of 11 eV, was used to study propagation of an artificially launched wave varying as ej(ωt + mθ - kz) at approximately the ion cyclotron frequency. The wave was transmitted between two similar internally placed helically wound antennas separated by 11 wavelengths. The coupling between them was enhanced by as much as 50 times in the presence of plasma. The m = 1 left-handed component was cut off when (ω > (ωci. Electron temperatures could be increased by more than 2 times with the m = 1 mode, presumably due to ion heating. Little pump-out was observed.