Effect of Biasing Voltage on Hydrogen (H β ) Temperature in IR-T1 Tokamak, Using Spectroscopy

In this research, the influence of the biasing voltage on hydrogen temperature and plasma confinement is investigated in the IR-T1 tokamak. The applied voltage was in the range of − 250 to + 250 V. Hydrogen (Hβ) temperature was estimated using measurements provided by the optical system based on a two-channel AvaSpec-ULS3648TEC-2-RS-USB2 visible light spectrometer on IR-T1 tokamak. The FWHM of Hβ spectral line was determined by normalizing and fitting the Gaussian distribution function to the experimental data. The hydrogen temperature was calculated in each state (Vbiasing = − 250 V and Vbiasing = + 250 V) at the plasma edge of IR-TI tokamak, using the effects of Doppler and instrument broadenings. Finally, the results were compared with the normal state (Vbiasing = 0 V). The spectroscopic results show a significant decrease in the spectral emission and subsequently improvement in confinement for positive biasing and significant decrease in plasma-edge temperature for negative biasing. These results illustrate the effect of radial induced electric field on plasma confinement.