Helicon experiments and simulations in nonuniform magnetic field configurations

Wave, antenna impedance, plasma density, and temperature anisotropy measure ments are carried out for a helicon plasma source in nonuniform and uniform static magnetic fields. Strong axial density gradients associated with the nonuniform magnetic fields are observed to affect wave fields, absorption, and source efficiency. The wave field and antenna input impedance measurem ents are compared with a new simulation code which also calculates Poynting power flow and wave absorption profiles. Wave amplitude measurements are s hown to decay more rapidly and the phase velocity varies over a wide range for the nonuniform static magnetic field case. (C) 1999 American Institute of Physics. [S1070-664X(99)00608-4].