ON THE ATOMIC STATE DENSITIES OF PLASMAS PRODUCED BY THE TORCHE A INJECTION AXIALE

The atomic state densities of helium and argon plasmas produced by the microwave driven plasma torch called the ''torche a injection axiale' ' are presented. They are obtained by absolute line intensity measurem ents of the excited states and by applying the ideal gas law to the gr ound state. It will be shown that the atomic state distribution functi on (ASDF) does not obey the Saha-Boltzmann law: the ASDF cannot be des cribed by one temperature. From the shape of the ASDF: it can be concl uded that the plasma is ionising. By extrapolating the measured state densities towards the ionisation limit, a minimum value of the electro n density can be determined.