Jd. Hey et al., DOPPLER BROADENING AND MAGNETIC-FIELD EFFECTS ON THE BALMER LINES EMITTED AT THE EDGE OF A TOKAMAK PLASMA, Contributions to Plasma Physics, 36(5), 1996, pp. 583-604
Profiles of the Palmer lines D-alpha(H-alpha), D-beta(H-beta) and D-ga
mma(H-gamma) have been measured in the scrape-off layer and within the
edge of the TEXTOR (upgrade) plasma, under Ohmic conditions and with
neutral-beam injection. Each line profile shows a strong Zeeman effect
in the vicinity of line centre, and a marked central dip when mainly
the sigma components are observed. The line core evidently originates
from cold atoms in the edge plasma, excited in the course of molecular
dissociation, while the broad pedestal on which the core rests is rad
iated by excited atoms produced through charge-exchange recombination
of deuterons (protons), transported outwards from the much hotter plas
ma interior, and by atoms heated directly by collisions with the deute
rons (protons). Core temperatures of about 0.5 eV and less are obtaine
d from Line profile analysis.