ABSTRACT

For inhomogeneous low-temperature plasmas, a technique is considered for the evaluation of plasma temperature distributions using lines in the plasma emission spectra. The technique allows determining the temperature distributions along an observation line directly from the observed emission avoiding an evaluation of the plasma local emissivity. For the technique application, the plasma has to be close to LTE and optically thin. The temperature distribution is supposed to have one maximum and a monotone fell around it. For the temperature evaluation, half-widths and shifts, as well as intensity of the chosen atomic spectral lines have to be measured. These values are used to find parameters accounting for the temperature distribution: the temperature maximum value, the distribution half-width and the parameter determining the distribution shape.
Numerical modelling has been performed to test the technique under consideration. Argon atmospheric pressure plasma and atomic lines with different broadening parameters have been chosen for the modelling. Stark broadening has been considered as a dominant factor. The numerical modelling results show the technique feasibility, its application range and error limits. Also positive results are presented of the technique test using some experimental data.