Spectroscopic study of CX excited impurity ions in MARFEs and detached plasmas of Tore Supra

This work has been stimulated by the increasing interest in diagnostic methods capable of measuring the density and temperature of divertor plasmas which are characterised by low electron temperature and high neutral density. Our study of the highly radiating cold and dense edge layers sustained by the ergodic divertor (ED) of TS has shown the importance of CX excited highly ionised impurities in this zone. Spectroscopic measurements of MARFE and detached plasma radiation show the existence of a highly ionised carbon flux from the hot plasma core into the cold edge layer. Space and wavelength resolved measurements of CVI (8-7, 5290 A) and (2-1, Lyα) radiation have clearly shown the difference between CX and electron collision excitation. Whereas electron collision excitation occurs in a corona with Te∼χi(CVI), CX collisions occur further out at the overlap of the neutral density layer and the outstreaming C6+ ions. (author) 3 refs., 6 figs