Estimation of neutral temperature from H_α emissions under the influence of magnetic fields in Aditya-U Tokamak

Neutral particle temperature in tokamak plasma can be measured through the estimation of Doppler broadening of the spectral line. This measurement is important considering the neutral particle manipulate the plasma edge properties through its interaction with plasma particle. Under the influence of magnetic field in tokamak, the shapes of the spectral lines emitting from the plasma are significantly modified due to the Zeeman splitting, in which a single spectral line splits into multiple components. A single component is having a certain broadening corresponds to value of the neutral or ion temperature. However, when all components added up, the apparent broadening did not reflect the actual temperature of the emitting species. To minimize such effect while estimating the neutral temperature from H_α emission (656.28 nm), a MATLAB simulation code has been developed to incorporate the Zeeman Effect in the temperature measurement. In this code all 48 components of Zeeman splitted spectral lines are considered and neutral temperature was estimated. In this paper we are presenting the simulation of the experimental results measured for recent Aditya-U tokamak experiments and the estimated neutral temperature of the Aditya-U tokamak plasmas under different experimental scenarios. (author)