Spectroscopic determination of electron density and temperature profiles in an inductively-coupled argon plasma

We have measured local profiles of the electron density and temperature in an atmospheric plasma using absolute intensities of highly excited argon states. The electron-density profile has been determined independently by spatially resolved measurements of the Stark broadening of the hydrogen-ß line. By comparing these two methods, deviations from local thermal equilibrium may be characterized. Experimental results from an inductively-coupled argon plasma are presented and indicate that the plasma is close to LTE.