Helicon plasma in a nonuniform magnetic field

The distributions of the electron density in a plasma produced by helicon w aves and the corresponding wave amplitudes and phases are studied experimen tally. The measurements were carried out in an argon plasma at a pressure o f 3 mtorr and at an input RF power of up to 600 W. The magnetic field was v aried in the range from 0 to 200 G. The efficiency of plasma production in both uniform and nonuniform fields is investigated. It is shown that, in a nonuniform magnetic field, the electron density can be substantially increa sed (up to 5 x 10(12) cm(-3)) by placing an antenna in the region in which the magnetic field is weaker than in the main plasma. (C) 2001 MAIK "Nauka/ Interperiodica".