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Title: Snowflake Divertor Configuration in NSTX

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.

Authors:
 [1];  [2];  [3];  [3];  [3];  [3];  [3];  [3];  [3];  [2];  [4];  [2];  [3];  [3];  [3];  [5];  [3];  [1];  [1]
  1. Lawrence Livermore National Laboratory (LLNL)
  2. ORNL
  3. Princeton Plasma Physics Laboratory (PPPL)
  4. Nova Photonics, Princeton, NJ
  5. University of Washington, Seattle
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1037042
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Conference
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
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; COATINGS; CONFIGURATION; CONFINEMENT; DIVERTORS; HEAT FLUX; LITHIUM; MAGNET COILS; MAGNETIC PROPERTIES; PLASMA; POWER DENSITY

Citation Formats

Soukhanovskii, V A, Ahn, Joonwook, Bell, R E, Gates, D A, Gerhardt, S, Kaita, R, Kolemen, E, Kugel, H W, LeBlanc, B, Maingi, Rajesh, Maqueda, R J, McLean, Adam G, Menard, J E, Mueller, D, Paul, S F, Raman, R, Roquemore, L, Ryutov, D D, and Scott, H A. Snowflake Divertor Configuration in NSTX. United States: N. p., 2011. Web.
Soukhanovskii, V A, Ahn, Joonwook, Bell, R E, Gates, D A, Gerhardt, S, Kaita, R, Kolemen, E, Kugel, H W, LeBlanc, B, Maingi, Rajesh, Maqueda, R J, McLean, Adam G, Menard, J E, Mueller, D, Paul, S F, Raman, R, Roquemore, L, Ryutov, D D, & Scott, H A. Snowflake Divertor Configuration in NSTX. United States.
Soukhanovskii, V A, Ahn, Joonwook, Bell, R E, Gates, D A, Gerhardt, S, Kaita, R, Kolemen, E, Kugel, H W, LeBlanc, B, Maingi, Rajesh, Maqueda, R J, McLean, Adam G, Menard, J E, Mueller, D, Paul, S F, Raman, R, Roquemore, L, Ryutov, D D, and Scott, H A. Sat . "Snowflake Divertor Configuration in NSTX". United States.
@article{osti_1037042,
title = {Snowflake Divertor Configuration in NSTX},
author = {Soukhanovskii, V A and Ahn, Joonwook and Bell, R E and Gates, D A and Gerhardt, S and Kaita, R and Kolemen, E and Kugel, H W and LeBlanc, B and Maingi, Rajesh and Maqueda, R J and McLean, Adam G and Menard, J E and Mueller, D and Paul, S F and Raman, R and Roquemore, L and Ryutov, D D and Scott, H A},
abstractNote = {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.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2011},
month = {1}
}

Conference:
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