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.