Abstract
The article describes the characteristics of optical diagnostics of the tokamak KTM and the results of measuring the plasma parameters of the tokamak KTM obtained with their help. The measurements of the parameters of the plasma discharge were carried out as part of the work at the second stage of the physical start-up of the tokamak KTM. Based on the obtained experimental data the elemental composition of the plasma was estimated by measuring line radiation in the visible range (380–700 nm), the moment of plasma breakdown was determined and the position and shape of the plasma column was estimated.