Characterization of Plasma Production by m=0 Standing Helicon Waves

Excitation of m=0 standing helicon waves (SHWs) of N=1 and 3 modes (m is the azimuthal mode number and N is the number of half-wavelengths in the axial direction) and production of high-density plasmas of the order of n p≃1013 cm3 have been investigated in a short cylindrical plasma column of 10 cm length [M. Nisoa, Y. Sakawa and T. Shoji: Jpn. J. Appl. Phys. 38 (1999) L777]. Excitation of different N modes of SHWs has caused an abrupt density jump with rf power P rf and axial static magnetic field B 0. The power-balance equation is solved using the n p dependence of plasma loading resistance R obtained numerically from a two-dimensional wave code. Calculated P rf and B 0 dependence of stable n p agrees well with measured ones. Measured hollow (parabolic) n p profile caused by the excitation of N=1 (N=3, 5 and travelling helicon wave) mode is explained in terms of the perpendicular (parallel) component of wave electric field E ⊥ (E z ). Power absorption due to E ⊥ and E z is dominant for the hollow and parabolic n p profiles, respectively.