Measurements of C v flows from thermal charge-exchange excitation in divertor plasmas

Certain transitions of C IV (C3+) from n=7 to n=6 (approximate to 7226 Angs trom) and from n=6 to n=5 (approximate to 4660 Angstrom) sometimes appear m uch brighter in tokamak divertors than expected for electron-impact excitat ion from the ground state. This situation occurs because of charge exchange between C V (C4+) and recycling thermal deuterium atoms in the n=2 level. As a result, it is possible to extend parallel flow measurements of carbon, which have previously been performed on C II-C IV ions using Doppler shift spectroscopy, to include flows of the He-like C V ions. The work described here includes modeling of the spectral features, correlation of state popu lations with classical Monte Carlo trajectory (CTMC) predictions, and appli cations to flow measurements in the DIII-D divertor [Plasma Physics Control led Nuclear Fusion Research 1986 (International Atomic Energy Agency, Vienn a, 1987), Vol. I, p. 159; Proceedings of the 18th IEEE/NPSS Symposium on Fu sion Engineering, Albuquerque (Institute of Electrical and Electronic Engin eers, Piscataway, 1999), p. 515]. (C) 2001 American Institute of Physics.