Effects of triangularity on confinement, density limit and profile stiffness of H-modes on ASDEX Upgrade
At ASDEX Upgrade, the influence of triangularity on the H-mode performance has been studied intensively. It has been found that confinement increases with "d" for a fixed line-averaged density. Though confinement decreases with increasing density for all analyzed values of "d", H-factors (ITERH-98P) at the Greenwald density could be raised to 1 for the highest "d" values achieved so far. The H-mode density limit could be increased by approximately equal to 20%. There is a scatter of about 30% on the confinement data, which is anti-correlated to the average density in the scrape-off layer or the neutral fluxes outside the plasma. For nearly all discharges analyzed so far, the temperature profiles are self-similar. This indication of profile stiffness could be verified by changing the heat-flux profile by changing the beam-coltage of the neutral-beam injection (NBI) at high density. At low density, first results indicate a deviation from this stiff behaviour.
Bibliographic Reference: Article: Plasma Physics Controlled Fusion, Vol 42 (2000) pp. A211-A216
Availability: Plasma Physics Controlled Fusion (Journal)
Record Number: 200012115 / Last updated on: 2000-07-12
Original language: en
Available languages: en