Abstract
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.
| Original language | English (US) |
|---|---|
| Pages (from-to) | S365-S368 |
| Journal | Journal of Nuclear Materials |
| Volume | 415 |
| Issue number | 1 SUPPL |
| DOIs | |
| State | Published - Aug 1 2011 |
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics
- General Materials Science
- Nuclear Energy and Engineering