Abstract
Modeling of transient impurity transport during large ELMs is used to explore basic processes which may determine ELM-averaged enrichment. The b2-Eirene code (solps4), used for DIII-D geometry, suggests that a complex sequence can occur during an ELM cycle in which a transiently detached phase, with relatively low enrichment, can occur even under nominally attached conditions. A slower recovery phase then follows, in which the effect of induced scrape-off layer flows can increase in importance. The model results are compared with available fast time-scale measurements. The observed increased enrichment with higher Z is similar to trends in basic particle reflection properties. Neon recycling processes may thus introduce a significant history effect, as illustrated by analysis of continuous, unforced neon accumulation in a DIII-D discharge with a well-characterized operational history.
Original language | English |
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Pages (from-to) | 1221-1228 |
Number of pages | 8 |
Journal | Journal of Nuclear Materials |
Volume | 313-316 |
Issue number | SUPPL. |
DOIs | |
State | Published - Mar 2003 |
Event | Plasma - Surface Interactions in Controlled Fusion Devices - Gifu, Japan Duration: May 26 2002 → May 31 2002 |
Funding
The B2-Eirene code is provided by the B2-Eirene development group: R. Schneider, D. Coster, X. Bonnin (IPP-Garching, Greifswald) and D. Reiter, P. Boerner (FZ-Juelich). This research was sponsored in part by the Office of Fusion Energy Sciences, US Department of Energy, under contract DE-AC05-00OR22725 with Oak Ridge National Laboratory managed by UT-Battelle, LLC.
Keywords
- B2-EIRENE code
- Boundary plasma
- Divertor
- Neon
- Plasma-wall interactions
- Recycling