A Spectral Diagnostic Method for Determining Internal Properties of Asymmetrical Plasmas

摘要

A numerical method has been developed for inverting the integral equation which relates the emitted spectral intensity to the internal emission coefficient for optically thin plasmas. The method is applicable to both symmetrical and asymmetrical plasmas with no prerequisite orientation of the source with respect to the laboratory coordinate system. The validity of the series representation of the emission coefficient has been checked by means of a hypothetical model consisting of a source whose emission coefficient is taken as a displaced symmetrical gaussian function. The method has been further tested by applying it to a symmetrical experimental argon arc which has been displaced with respect to the coordinate system to simulate an asymmetrical plasma. The fully developed method has been used as a practical diagnostic tool to investigate the internal properties of a generally asymmetrical experimental plasma produced by interacting the free-burning argon arc with an external magnetic field. Initial steps have been taken to develop a practical method for diagnosing optically thick plasmas without requiring any direct measurements of the transmission along the path of integration by means of reflection optics or an external source of radiation. (Author)