2D imaging of a helicon discharge

Summary form only given, as follows. Two dimensional images from the ionized argon light of a helicon discharge are made both along and across the magnetic field with various antenna configurations. It is shown that even at high densities where the discharge is said to be operating predominantly in a "wave-mode", or at least primarily inductively coupled, capacitive coupling from the antenna can still have a significant effect on the plasma profile. Transverse images also show that with all other conditions being the same a helical antenna produces brighter plasmas than a straight Nagoya Type III antenna, and with the helical antenna a configuration corresponding to excitation of the m=+1 helicon mode produces a longer brighter plasma than the m=-1 configuration. A connection between these results and simplified helicon wave theory with the calculated power spectra of the antennas is discussed.