D Experimental Study in Tore-Supra Ergodic Divertor Plasmas: Molecular Deuterium Density Measurements

Autor: J.T. Hogan, M. G. O'Mullane, M. Koubiti, A. Escarguel, M. Mattioli, B. Pégourié, A. Azéroual, H. Capes, R. Guirlet, C. De Michelis, Roland Stamm, Tore-Supra team
Rok vydání: 2002
Předmět:
Zdroj: Contributions to Plasma Physics. 42:622-629
ISSN: 1521-3986
0863-1042
DOI: 10.1002/1521-3986(200211)42:6/7<622::aid-ctpp622>3.0.co;2-1
Popis: The deuterium Dα line emitted in front of an equatorial neutraliser plate in Ergodic Divertor Tore Supra plasmas is a common diagnostic of recycling particles in present Tokamaks. First, the possible perturbation of the Dα spectral lineshape by the nearby HeII line Brβ has been studied. Although its effect on the Da line profile shape is evaluated to be non negligible in plasmas with large Helium contents, it is concluded that it should be of no influence in usual fusion plasmas. Second, a detailed study of the Da spectral lineshape has been performed to obtain temperatures and densities of the different neutral deuterium species. A synthetic profile method taking into account Zeeman and Doppler effects has been used. This shows that two deuterium populations with specific behaviours have to be considered: the first one ('cold atoms') is composed of atomic deuterium coming from D 2 desorbed from the neutraliser plate, while the second one ('warm atoms') is composed of charge exchange (CX) and reflected deuterium. The Doppler temperature of cold atoms increases with the edge electron density, n edge e (1.4 eV 10 18 m -3 ) is found for the whole range of edge electron temperature (10 eV < T e < 40 eV) while the ratio of the atomic to the molecular densities is around 1.8. The density of atoms coming from molecular dissociation is ∼ 0.8 times the density of atoms created by charge exchange or reflection of deuterons on the neutraliser.
Databáze: OpenAIRE
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