Snowflake Divertor Configuration in NSTX
- Lawrence Livermore National Laboratory (LLNL)
- ORNL
- Princeton Plasma Physics Laboratory (PPPL)
- Nova Photonics, Princeton, NJ
- University of Washington, Seattle
Steady-state handling of divertor heat flux is a critical issue for present and future conventional and spherical tokamaks with compact high power density divertors. A novel 'snowflake' divertor (SFD) configuration that takes advantage of magnetic properties of a second-order poloidal null has been predicted to have a larger plasma-wetted area and a larger divertor volume, in comparison with a standard first-order poloidal X-point divertor configuration. The SFD was obtained in 0.8 MA, 4-6 MW NBI-heated H-mode discharges in NSTX using two divertor magnetic coils. The SFD led to a partial detachment of the outer strike point even in low-collisionality scrape-off layer plasma obtained with lithium coatings in NSTX. Significant divertor peak heat flux reduction and impurity screening have been achieved simultaneously with good core confinement and MHD properties.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1037042
- Resource Relation:
- Conference: 19th International Conference on Plasma-Surface Interactions in Controlled Fusion Devices (PSI), San Diego, CA, USA, 20100524, 20100528
- Country of Publication:
- United States
- Language:
- English
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