Excitation of Electron Cyclotron Harmonic Waves in Plasmas

Abstract

When a magnetoplasma is irradiated by an external microwave, the frequency of the excited subsidiary resonance waves is the same as that of the external microwave, even if the receiving frequency is not equal to the frequency of the external microwave. Experimental studies of their dispersion relation show that there is a forbidden band proposed theoretically by Bernstein. In order to investigate an excitation mechanism of these resonance waves, the half-width of the intensity distribution curves are measured for the various plasma parameters. These half-width are independent of the gas pressure, but strongly depend on the diameter of the plasma column.