Electron number density and collision frequency measurements in a microwave surface wave discharge

The results of the electron number density and the electron-neutral collision frequency measurements in an argon plasma column produced by a microwave surface wave are reported in this paper. Two different measurement methods were used in order to determine the electron number density as a function of the plasma column axial position: the first uses a moving axial microwave probe mounted over the glass tube. The second uses a double Langmuir probe system. Two dispersion equations for the wave propagation were also obtained: one where the electron-neutral atoms collision frequency is much lower than the microwave frequency (v<\n\n\t\t