Ripple of Electron Temperature in R. F. Plasmas

Since the electron temperature in r.f. plasmas oscillates around the d.c. one, the ripple, R T is calculated from the energy balance. Next, the electron density ripple, R n is deduced from the difference between the ionization and diffusion loss. The frequency and pressure ranges for R n ≪ R T are found, where the light intensity only follows the electron temperature, if the life time of the excited atoms is shorter than the period of the highest frequency. Then R T can be determined from the observed wave pattern of the light at a specific wave length. Here 5852.5 Å in neon and 5016 Å in herium are selected. Finally, the loss factors of electrons κ, which are determined from the experimental values of R T , are compared with the theoretical ones with a good agreement.