The Role of RF in the Optimized Shear Scenario on JET
RF heating and current drive with ion cyclotron waves and Lower Hybrid waves have been crucial for the development of the optimized shear scenario on ET to high performance. Peaked electron temperature profiles and improved energy confinement could d be obtained with electron heating both from LHCD and ICRH during plasma current ramp up. ICRH and NBI comparisons allow to separate heating and fueling and suggest a dominant role of core heating in the formation of an Internal Transport Barrier. ICRH and NBI powers are the equivalent. Pressure profile control by varying the composition of centrally peaked ICRF and broader NBI deposition improves MHD stability. Current profile modifications in a wide range have been obtained with LHCD and in combination with NBI during current ramp up. During the high performance phase, however, LH coupling degrades strongly due to the steep edge density gradient resulting in a drop of the density in front of the LH antenna to the cut-off density. High fusion performance achieving simultaneously high beta values and bootstrap currents is predicted in scenario modelling using pressure and current profile control with ICRF and LHCD.
Bibliographic Reference: Report: JET-P(99)15, 8pp.
Availability: Available from the Librarian, JET Laboratory, Abingdon (GB)
Record Number: 199911464 / Last updated on: 1999-10-08
Original language: en
Available languages: en