Evolution of 2D deuterium and impurity radiation profiles during transitions from attached to detached divertor operation in DIII-D
- Lawrence Livermore National Lab., CA (United States); and others
This paper presents the detailed evolution of conditions along both the inner and outer divertor legs during the transition from attached ELMing H-mode to partially detached divertor (PDD) operation in DIII-D. Visible emission profiles in a poloidal plane show that in ELMing H-mode prior to deuterium gas injection, CIII emission peaks in the inner SOL near the X-point and deuterium emission (from ionization and recombination) peaks at the inner target plate near the inner strike point (ISP). The spatial profiles of the recombination and ionization zones, determined by forming images of the ratio of intensities from simultaneous images of D{sub {alpha}} and D{sub {gamma}} emission, show that recombination dominates the inner leg emission near the target; ionization dominates in a poloidally narrow zone upstream in the inner leg. After deuterium injection, when the PDD transition begins, the profiles of carbon visible emission show first an increase in the inner SOL near the X-point, followed by increases in emission in the lower regions of the outer leg. Deuterium emission at the transition onset decreases at th4e ISP and increases across the private flux region below the X-point. As the transition to PDD conditions proceeds the deuterium emission increases in the private flux region; recombination dominates near the floor and ionization higher near the X-point. Carbon emission appears along both divertor legs and at the X-point. In the final quasi-steady PDD state, the recombination emission in the outer leg is near the separatrix and along the target plate; emission from collisional excitation dominates in the upper part of the outer leg just below the X-point, and carbon emission is localized at the X-point. These results suggest that transport of neutral deuterium between the inner and outer divertor legs through the private flux region plays an important role in the initiation of outer leg detachment in DIII-D.
- Research Organization:
- General Atomics, San Diego, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of California, San Diego, CA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC03-89ER51114; W-7405-ENG-48; AC05-96OR22464; FG03-95ER54294
- OSTI ID:
- 291093
- Report Number(s):
- GA-A-22861; CONF-980560-; ON: DE99000496; BR: 35AT10020; 35AT15040; AT101014D; AT101015A; TRN: 99:002290
- Resource Relation:
- Conference: 13. international conference on plasma surface interactions, San Diego, CA (United States), 18-22 May 1998; Other Information: PBD: Aug 1998
- Country of Publication:
- United States
- Language:
- English
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