DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 368: Dependence of C deposition and D co-deposition rates on the surface temperature | ||
| Name: | Dmitry Rudakov ( |
Affiliation: | University of California, San Diego |
| Research Area: | Hydrogenic Retention | Presentation time: | Requested | Co-Author(s): | A. Litnovsky, V. Philipps, W. West, C. Wong, R. Boivin, W. Wampler, D. Buchenauer |
| Description: | Expose differentially heated metal strip mounted on DiMES holder to detached ELMing H-mode discharges. Because of the surface temperature variation, net deposition rates of C and D, D/C ratios, and deposited layer thickness will vary along the strip. | ||
| Experimental Approach/Plan: | Insert the DIMES holder with metal strip into the private flux zone of high-density LSN ELMing H-mode plasmas. Expose for ~8 plasma discharges. Remove and analyze deposit thickness and C and D areal density by various techniques (ellipsometry, IBA, SIMS, XPS). | ||
| Background: | During the 2004-07 experimental campaigns it was shown that a moderate increase of the surface temperature has a dramatic effect on C deposition and D co-deposition at recessed surfaces in a tokamak divertor under detachment. C deposition was observed on molybdenum mirrors recessed below the divertor floor at room temperature, and was fully suppressed at elevated temperature between 90 - 180ºC. At 200ºC carbon deposition down a simulated tile gap was reduced by about a factor of 2-4 and D co-deposition by an order of magnitude compared to those at room temperature. Here we are proposing to measure a continuous dependence of the deposition/co-deposition rates on the surface temperature. | ||
| Resource Requirements: | 1/2 day experiment; high density ELMing H-mode, NBI | ||
| Diagnostic Requirements: | DIMES with a specially built head, all available lower divertor diagnostics | ||
| Analysis Requirements: | Various surface analyses: IBA, ellipsometry, SIMS, XPS | ||
| Other Requirements: | -- | ||
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