Observation of deuterium molecule emission spectra under an active feedback control of H-mod plasma divertor detachment experiment on the EAST tokamak

Abstract

Based on neon gas puffing, an active feedback control of H-mod plasma divertor detachment experiment had been successfully operated on EAST tokamak. During the feedback control discharge, the plasma was detached by puffing neon gas and the strike point splitting phenomenon on divertor target was also clearly observed by divertor probes diagnostic. In boundary region, many neutral particle processes (atom and molecule) were happened and accompanied by their emission spectra under the detachment discharge. By studying these emission spectra, it is helpful for us to understand the role of atom and molecule in boundary recycling, which is important for studying the physical mechanism of divertor detachment. In present work, Fulcher-α system (d(3p)3∏u ± -a(2s)3∑g +) of D2 emission spectra in the range from 601 to 606 nm were observed, identified and fitted in the detachment experiment for the first time on EAST, and the spectra in the Q(0-0) band (d3∏u --a(2s)3∑g +) in the Q branch of the Fulcher-α system were used for detailed analysis for acquire the boundary region temperature T e (below 5eV) which could not be provided very well by other diagnostics on EAST. An electronic version deuterium molecular spectral lines database was established to identify the spectral lines and a multi-peak fitting program was developed to fit and analyze the observed spectra.