Carbonization of the DIII-D tokamak
The DIII-D tokamak has been carbonised by the application of a carbon film covering all plasma facing surfaces. This was done in order to reduce the metal impurity influx and central metal accumulation, especially during beam heated D(0) to D(+) H-mode discharges. After carbonisation, nickel impurity line radiation was reduced by a factor of 10 during the ohmic phase of the discharge and up to a factor of 30 during the H-mode phase. The reduction of metal impurities also produced a reduction of total radiated power and allowed high current operation. The highest plasma current in a double null divertor and the highest stored energy ever achieved on DIII-D were observed, 3 MA and 3.6 MJ respectively. A reactor relevant toroidal beta of 5.1% at full field, (2.1 T), was obtained. On the first day after carbonisation, H-mode density profiles were more peaked than in pre-carbonisation discharges.
Bibliographic Reference: Article: Journal of Nuclear Materials, Vol. 176 & 177 (1990) pp. 311-318
Record Number: 199110895 / Last updated on: 1994-12-02
Original language: en
Available languages: en