CRITICAL PARAMETERS FOR THE L AND H CONFINEMENT IN NEUTRAL BEAM HEATED TOKAMAKS
Correlations of the anomalous transport in L and H (low and high confinement) discharges of ASDEX with the profile parameters eta-e,-i = dln T-e,i/dln n are investigated by means of transport modelling. It is found that the transitions between ohmic and L transport occur when T-i/T-e in the bulk plasma approaches unity. The time evolution of the electron heat diffusivity and the operational limits of the H mode show that eta-e and eta-i are connected with the H transport. Small eta-e,i around unity are obtained in the H regime, while large eta values result in the L regime. The connection with eta-e and eta-i suggests that drift instabilities (dissipative trapped electron modes) are involved in the anomalous transport with neutral injection.
Bibliographic Reference: COURSE AND WORKSHOP ON BASIC PHYSICAL PROCESSES OF TOROIDAL FUSION PLASMAS, VARENNA (ITALY), AUG. 26-SEPT. 3, 1985 VOL. I, PP. 217-223 EUR 10418 EN (1986) FS, VOL. I AND VOL. II, 733 P., BFR 3600 FOR BOTH VOLUMES, EUROFFICE, LUXEMBOURG, POB 1003
Record Number: 1989125079500 / Last updated on: 1987-12-01
Available languages: en