Speaker
Dr
Choong-Seock Chang
(Princeton Plasma Physics Laboratory)
Description
The edge gyrokinetic code XGC1 shows that the divertor heat flux width λq in between ELMs of Type I ELMy H-modes in two representative types of present tokamaks (DIII-D type for conventional aspect ratio and NSTX type for tight aspect ratio) is set mostly by the ion neoclassical orbit spread, which is proportional to 1/Ip, while the blobby turbulent spread plays a minor role. This explains the 1/Ip scaling of the heat flux width observed in present tokamaks. On the other hand, the XGC1 studies for ITER H-mode like plasmas show that λq is mostly set by the blobby turbulent spread, with the heat flux width being about 5X wider than that extrapolated from the 1/Ip scaling. This result suggests that the achievement of cold divertor plasmas and partial detachment required for power load and W impurity source control may be more readily achieved and be of simpler control issue than predicted on the basis of the 1/IP scaling. A systematic ongoing validation study of the XGC1 results on various existing tokamaks will also be presented, including JET that is the closest existing device to ITER. [This work is supported by US DOE, and computing resources supported by OLCF at ONRL.]
| Country or International Organization | USA |
|---|---|
| Paper Number | TH/2-1 |
Primary author
Dr
Choong-Seock Chang
(Princeton Plasma Physics Laboratory)
Co-authors
Dr
Alberto Loarte
(ITER Organization)
Dr
Florian Koechl
(Vienna University of Technology, Institute of Atomic and Subatomic Physics)
Dr
Michele Romanelli
(CCFE)
Dr
Rajesh Maingi
(Princeton Plasma Physics Laboratory)
Dr
Seung-Hoe Ku
(Princeton Plasma Physics Laboratory)
Dr
Vassili Parail
(CCFE)
