An experimental study of asymmetry in an argon inductively coupled plasma torch using a relaxation method

A relaxation method is used to undertake an experimental study of the degree of cylindrical symmetry present in an argon inductively coupled plasma torch, ICP. This technique, in effect a direct comparison between two different parameters, the electron (T_e) and gas (T_g) temperatures in the torch, is shown to be a very sensitive indicator of axisymmetry. Measurements using this technique delineate areas of axisymmetry in the ICP, and show that axisymmetry is significantly dependent on the observation height and coolant gas flow-rate.