DIAGNOSTICS OF A NONEQUILIBRIUM INDUCTIVELY-COUPLED PLASMAS IN ARGON

apparatus including a robot manipulated optical system has been built to provide absolute emission data from an inductively coupled plasma o perating in argon in non-equilibrium conditions. Data for the two-dime nsional population densities of one of the excited states of neutral a rgon ArI are presented together with the Langmuir probe data for elect ron density and plasma potential. Measurements were performed at 500 m Torr and 50 mTorr and with 100 seem flow of argon under the constant p ower condition, 100 W. The data show that excitation profile is almost identical to the radial profile of electron density. At higher pressu re maximum excitation and electron density are produced close to the w alls, while at low pressure maximum excitation is at the center of the vessel and a high field is formed close to the walls. (C) 1996 Americ an Institute of Physics.