QUASI-STATIONARY D-2 PELLET INJECTION INTO ASDEX DIVERTOR DISCHARGES
The authors report of deuterium discharges in ASDEX where the particle inventory is sustained entirely, after an initial gas fuelling phase, by the injection of a series of up to 80 frozen D-2 pellets, 1 mm in diameter and 1.2 mm long (N-2 <or= 4.5 x 10**19), at intervals ranging from 20 to 50 ms, and speeds to 720 m/s, by means of centrifuge. Investigations performed on Ohmic, NI, and ICRH heated discharges have shown that most important parameter characterizing the discharges is the ratio of the pellet penetration depth, DELTA, to the fall-off length for the neutral particles in a gas fuelled case (Typically 5 - 8 cm in ASDEX). For shallow penetration, only minor differences, relative to gas fuelled shots, are observed. In contrast, with deep penetration (e.g. DELTA >or= a/2) the density profile is more peaked, and the temperature profile flattened, when compared with gas fuelled discharges at the same line integrated density, n-e. The discussion here concentrates on these characteristic "deep fuelling discharges". Because of the limited pellet size and velocities presently available, these deep fuelling discharges are Ohmically heated with T-e <or= 1 keV. In the following aspects of recycling, and density limits.
Bibliographic Reference: 12TH EUROPEAN CONFERENCE ON CONTROLLED FUSION AND PLASMA PHYSICS, BUDAPEST (HUNGARY), SEPT. 2-6, 1985 WRITE TO MAX-PLANCK-INSTITUT FUER PLASMAPHYSIK, 8046 GARCHING BEI MUENCHEN (GERMANY), MENTIONING REPORT IPP III/107, 1985, PP. 45-48.
Record Number: 1989124096700 / Last updated on: 1987-01-01
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