RESULTS FROM THE DITE BUNDLE DIVERTOR WITH FUELLING IN THE DIVERTOR
The DITE bundle divertor MkII has been operated with high power neutral beam injection, up to 2.1 MW, and with gaseous fuelling in the divertor. Discharges with good confinement have been used to study the properties of the plasma exhaust channel in the presence of a high density of neutral molecules in the divertor, up to about 1 X 10$u2**1 m**-3. An inner layer of the channel carries a large part of the heat exhaust by collisionless convection at a power density about 100 MW m**-2 and particle flux about 10**24 m**-2s**-1. Ionisation in the divertor has little effect on this layer. A collisional, low power density outer layer is strongly affected by the neutral particles in the divertor, with plasma flow out of the divertor at high neutral pressure, and ionisation losses supplied by electron heat transport from the torus. This layer has not previously been demonstrated in the plasma exhaust channel of a fusion research device. Calculations using the DEGAS code predict blocking of the divertor ducts by the exhaust plasma: retention of neutral particles in the divertor is seen experimentally. The amount of ionisation in the divertor is however lower than predicted, and it is shown that collisional interaction between neutral particles from the diverted plasma and the molecular background could be responsible for this reduction.
Bibliographic Reference: JOURNAL OF NUCLEAR MATERIALS, VOL. 128 & 129 (1984), PP. 359-367
Record Number: 1989124050200 / Last updated on: 1987-01-01
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