HELICON WAVE MEASUREMENTS IN AN INDUCTIVELY-COUPLED MAGNETOPLASMA

Small-amplitude test waves at 30-100 MHz are externally excited in an inductive rf plasma for a magnetic field of similar to 100 G, to obtain a full dispersion relation for helicon waves. Measured wavelengths agree well with theoretical ones, not only for the test waves but also for large-amplitude principal waves at the discharge frequency of 13.56 MHz. Absolute measurements of the radial magnetic field B-r of the large-amplitude helicon wave are carried out, and the r, theta and z components of the wave electric field are estimated to be E(r) similar to E(theta) similar to 8 V cm(-1) and E(z) similar to 0.7 V cm(-1) at an rf power of 800 W.