Spatial profiles of light impurity ions in the Alcator A tokamak plasma

• Published in: Nuclear fusion Vol. 20; no. 2; pp. 189 - 195
• Main Authors: Chen, K.I, Terry, J.L, Moos, H.W, Marmar, E.S
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.02.1980
• ISSN: 0029-5515; 1741-4326
• DOI: 10.1088/0029-5515/20/2/007

Spatial profiles of the concentrations of the highly ionized light impurities (O V, O VI, N V) have been obtained in the Alcator A tokamak by using an absolutely calibrated 0.4-m normal-incidence ultraviolet monochromator. In the inversion process, account has been taken of the observed up-down asymmetries in the UV emissions from these impurity ions. The concentrations of oxygen and nitrogen at the periphery relative to the local electron density are found to be 0.05-0.1% and 0.08-0.15%, respectively, at the time of the peak electron density. The positions and breadths of these shells have been studied as functions of electron density and plasma current. The shells show sharply defined outer edges near the local virtual limiter radius while the inner edges appear to be determined by the temperature profile.