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P: Plasmaphysik
P 1: Magnetic Confinement and Plasma Wall Interaction
P 1.8: Vortrag
Montag, 2. April 2001, 18:25–18:40, 2053
The behaviour of deuterium in front of a heatable test limiter in TEXTOR — •S. Brezinsek1, Ph. Mertens1, A. Pospieszczyk1, G. Sergienko2, and Th. Greenland3 — 1Institut für Plasmaphysik, Forschungszentrum Jülich GmbH, EURATOM Assoziation, Trilateral Euregio Cluster — 2Institute for High Temperatures, Moscow, Russia, Association IVTAN — 3Blackett. Lab., Imperial College, London, UK
The behaviour of atomic and molecular deuterium in front of an actively heatable test limiter in TEXTOR will be discussed. During the heat-up from 600 K to 1500 K a significant change in the intensity of atomic Dα , Dγ , and molecular deuterium, characterised by the Q(0−0)-branch of the observed Fulcher-band (3p3Π u→ 2s3Σg+), occurs. The dependence of the rotational population of the upper state on the surface temperature will be described and compared with the results of a gas blow experiment. Within the two series of identical TEXTOR plasma conditions no change in the behaviour due to the variation of the plasma edge parameters ne and Te was detected. The analysis of the simultaneously measured line profiles of Dα shows a change of the energy distribution of the atoms at temperatures above 1100 K. The molecular flux in the same range drops by about 50%. At low temperatures, the release of atoms produced via dissociation from vibrationally excited molecules dominates, whereas at high temperatures, the direct release of the atoms from the surface by desorption is the main release mechanism and the energy of the atoms reflects nearly the surface temperature. Similar results have been found for hydrogen plasmas [1].
[1] Pospieszczyk, A. et al, J. Nucl. Mater. 266-9 (1999) 138