ROLE OF NEUTRALS IN CORE FUELING AND PEDESTAL STRUCTURE IN H-MODE DIII-D DISCHARGES
OAK A271 ROLE OF NEUTRALS IN CORE FUELING AND PEDESTAL STRUCTURE IN H-MODE DIII-D DISCHARGES. The 2-D fluid code UEDGE was used to analyze DIII-D experiments to determine the role of neutrals in core fueling, core impurities, and also the H-mode pedestal structure. The authors compared the effects of divertor closure on the fueling rate and impurity density of high-triangularity, H-mode plasmas. UEDGE simulations indicate that the decrease in both deuterium core fueling ({approx} 15%-20%) and core carbon density ({approx} 15%-30%) with the closed divertor compared to the open divertor configuration is due to greater divertor screening of neutrals. They also compared UEDGE results with a simple analytic model of the H-mode pedestal structure. The model predicts both the width and gradient of the transport barrier in n{sub e} as a function of the pedestal density. The more sophisticated UEDGE simulations of H-mode discharges corroborate the simple analytic model, which is consistent with the hypothesis that fueling processes play a role in H-mode transport barrier formation.
- Research Organization:
- General Atomics, San Diego, CA (United States)
- Sponsoring Organization:
- (US)
- DOE Contract Number:
- AC03-99ER54463
- OSTI ID:
- 813646
- Resource Relation:
- Conference: THIS IS A PREPRINT OF A PAPER PRESENTED AT THE 15TH INTERNATIONAL CONFERENCE ON PLASMA SURFACE INTERACTIONS IN CONTROLLED FUSION DEVICES, GIFU (JP), 05/27/2002--05/31/2002; Other Information: PBD: 1 Oct 2002
- Country of Publication:
- United States
- Language:
- English
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