Investigation of the effect of pre-fill gas in VEST discharges by predictive transport simulations

Abstract

The predictive modeling of the VEST (Chung et al. in Plasma Sci Technol 15(3):244, 2013) device is presented. The integrated simulation tool was organized to conduct the 1D transport simulation considering neoclassical and turbulent transport, and pre-fill gas neutrals. The 1D transport equation and a detailed setup for the predictive analysis were addressed. By varying pre-fill gas levels, a set of predictive simulations was conducted. The electron density, electron and ion temperatures from Thomson scattering, and ion Doppler spectroscopy diagnostics were compared with the predictive simulation results. The discrepancies upon comparing the measurements with the simulations and further required efforts were discussed.