Basic concepts of temperature determination from self-reversed spectral lines

Abstract

Complex high-pressure plasmas have become increasingly important in technical applications such as high-intensity discharge lamps. The knowledge of temperature distributions is of basic interest for the understanding of the physical mechanisms in these plasmas and for a selective manipulation of their properties. It is shown that self-reversed spectral lines provide a powerful diagnostic tool for temperature determination. The two most important approaches for the corresponding data analysis are reviewed and their limitations are discussed. On the basis of these approaches a new method is proposed which avoids the main limitations especially in the application to resonance lines. The temperature has been determined in a Hg/Ar and a Hg/Ar/TlI high-pressure discharge. Measured spectral radiances of the Hg 546.1 and 253.7 nm as well as Tl 377.6 nm lines are analysed and the potentials of the different methods are demonstrated.