Visible range spectrum of the T-10 tokamak plasma

Abstract

One of the issues in studies of the modern plasma devices is linked with the impurities behavior and its entrance to the central plasma from the walls of the vacuum chamber. High density of the impurities affects the plasma discharge characteristics and mainly determines the efficiency of the plasma confinement. This article presents the impurity components diagnostics of the T-10 tokamak plasma, which is based on spectroscopic measurements in visible range of wavelengths with low spectral resolution. The radiation in range 390-710 nm of steady-state ohmic discharges is collected in section A of the tokamak equipped with graphite limiters. Monochromator MDR-206 without the output gap is used for the light detection in combination with the Proscan HS 101H CCD camera. Measured spectra shows the working gas lines of deuterium and well visible lines of the impurities: carbon (the main T-10 plasma contaminant), lithium, nitrogen and oxygen. Of particular interest are the oxygen and nitrogen lines, which shall not be observed under normal conditions and which indicate poor preparation of the vacuum chamber for operation mode. The diagnostics described in this article is required for normal operation on the tokamak for monitoring the plasma impurity components behavior during the experimental period and for rapid response in case of significant change in the lines intensities.