The concept of the 'resonance' wave discharge is introduced to explain the high absorption efficiency of inductively coupled helicon plasma source. This discharge is supported by long-scale weakly damped eigenmodes excited in plasma resonator. The RF power absorbed in it is inversely proportional to electron collision frequency. The fields excited by simple single-loop inner antenna and its impedance are calculated in a cylindrical metal resonator. At low collision frequencies the field amplitudes and antenna resistance are shown to peak sharply near the helicon dispersion branches.
Experimental observation of left polarized wave absorption near electron cyclotron resonance frequency in helicon antenna produced plasma