Two different kinds of plasmas created by the microwave driven Torche a Injection Axiale (TIA) are investigated: one with helium and the other with argon as the main gas. Using absolute line intensity measurements the densities of the excited states are determined. Applying the ideal gas law gives the ground state density. It is found that both plasmas are ionising and that the excitation temperatures range from 3000 to 11000 K. The electron temperature
and the electron density are determined using Thomson scattering. In the plasma with helium as the main gas, average densities between 0.64 and 5.1 × 1020 m−3
and temperatures around 25000 K are found. In an argon plasma the electron temperature is lower and the electron density is higher: 17000 K and around
1021 m−3 respectively. Radial profiles of the electron density, obtained by focusing the laser beam, appear to have a donut-like shape.