Scaling of edge ion and electron temperatures and impurity content during ICRF heating in TEXTOR
On TEXTOR changing from an all-metal to an all-carbon surrounding resulted in low-impurity stationary conditions without high-Z impurity problems. The use of boronisation reduced the influx of carbon and especially oxygen giving the possibility of coupling higher power to the plasma and enhancing the energy confinement. Without eliminating the mechanisms responsible for ICRF-specific impurity production and in spite of the fact that the boundary plasma properties are affected by ICRH, the RF-specific impurity production is almost completely suppressed. In this paper an attempt is made to correlate the edge temperatures and densities with the global behaviour of radiated power and impurity content. The data discussed refer to many series of ICRF-heated discharges with similar wall conditioning (boronisation) using pi-phased antenna pairs, one with and one without Faraday shield. The plasma current is 350 kA, B(T) = 2.25 T and the frequency 32.5 MHz. A comparison with NBI-heated discharges is also made.
Bibliographic Reference: Article: Proceedings of the Europhysics Topical Conference on Radiofrequency Heating and Current Drive of Fusion Devices (1992) pp. 133-136
Record Number: 199310453 / Last updated on: 1994-11-29
Original language: en
Available languages: en