Scrape-Off Layer Features of the QH-Mode

Conference · Thu May 23 00:00:00 EDT 2002

DOI:https://doi.org/10.1016/S0022-3115(02)01474-5· OSTI ID:15005358

Lasnier, C J; Burrell, K H; deGrassie, J S; Leonard, A W; Moyer, R A; Porter, G D; Watkins, J G

The quiescent high confinement (QH-mode) and quiescent double barrier (QDB) modes in DIII-D have long-duration H-mode confinement without ELMs, possibly an alternative operating mode in future tokamaks for avoiding damage by ELMS. Instead of ELMs, there is an edge harmonic oscillation (EHO), which is a continuous electromagnetic mode with associated density fluctuations. The edge pedestal is similar to ELMing H-mode, but at very low density to daw. We see C{sup +6} ion temperatures of 3-7 keV in scrape-off layer (SOL), 100 kV/m radial electric fields just inside the separatrix, and a hot area on the divertor baffle whose heating correlates with the presence of the EHO. We attribute the baffle heating to perturbation of trapped ion orbits by the EHO, allowing particles to strike the baffle. The outboard scrape-off layer is wider than the inboard, probably due to lack of trapped ions on the inside.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 15005358
• Report Number(s): UCRL-JC-148483; TRN: US0305402
• Resource Relation: Journal Volume: 313-316; Conference: 15th International Conference on Plasma Surface Interactions (PSI) in Controlled Fusion Devices, Gifu (JP), 05/27/2002--05/31/2002; Other Information: PBD: 23 May 2002
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BAFFLES
DIVERTORS
DOUBLET-3 DEVICE
ELECTRIC FIELDS
FLUCTUATIONS
HARMONICS
ION TEMPERATURE
H-MODE PLASMA CONFINEMENT
PLASMA SCRAPE-OFF LAYER
EDGE LOCALIZED MODES