Plasma Production by m=0 Standing Helicon Waves

m =0 standing helicon waves (SHWs) are used to produce high-density Ar plasmas, of the order of 10 13 cm -3 , in a bounded cylindrical plasma column. Axial mode number N =1, 3, and 5 ( N is the number of half-wavelengths in the plasma column) SHWs are strongly excited for plasma length L =10–26 cm with the rf power P rf ≤3.5 kW and external static magnetic field B 0 =237 G. Hollow and parabolic density profiles that depend on the axial mode of SHW are observed. The standing wave ratio decreases with L , and travelling helicon waves dominate the plasma production for L >26 cm. The measured results are compared with a two-dimensional wave calculation.