A simple method for the measurement of the electron temperature in a helium plasma by means of laser atomic absorption spectroscopy

It is shown that, for plasmas in which electron-atom collisions dominate over other collision processes, the electron temperature can be derived from the density of metastable helium states measured with laser atomic absorption spectroscopy. The model describing the electron temperature as a function of the density of the metastable helium states is independent of the electron density and is valid for electron temperatures -10 eV and for electron densities to within an error of 20%. For an extended parameter range a more complex model, additionally requiring knowledge of the electron density, may be used.