ON THE ELECTRON TEMPERATURES AND DENSITIES IN PLASMAS PRODUCED BY THETORCHE-A-INJECTION-AXIALE

The electron temperature and the electron density of plasmas created b y the ''Torche a Injection Axiale'' (TIA) are determined using Thomson scattering. In the plasma with helium as the main gas, temperatures o f around 25 000 K and densities of between 0.64 and 5.1 x 10(20) m(-3) are found. In an argon plasma the electron temperature is lower and t he electron density is higher: 17000 K and around 10(21) m(-3) respect ively. From these results it can be established that the ionisation ra tes of both plasmas are much larger than the recombination rates, whic h means that the plasmas are far from Saha equilibrium. However, devia tions from a Maxwell electron energy distribution function, as reporte d for the ''Microwave Plasma Torch'' (MPT), are not found in the TIA. The excitation and ionisation power of the TIA appears to be stronger than that of the MPT.