DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 269: Enhanced erosion from deuterium saturated materials during ELMs | ||
| Name: | Karl Umstadter ( |
Affiliation: | University of California, San Diego |
| Research Area: | Hydrogenic Retention | Presentation time: | Not requested | Co-Author(s): | Clement Wong, George Tynan, Russ Doerner |
| Description: | All prior heat pulse testing of PFCs have been completed in vacuum environments without the presence of a background plasma. ELMs will not be this kind of isolated event and one should know the effect of a plasma background during these transients. The retention of gas in PFCs may lead to enhanced erosion or explosions of material that will behave differently if ionized near the surface. Current models may underestimate the damage caused by ELMs due to this phenomena. | ||
| Experimental Approach/Plan: | DIMES samples of graphite and tungsten will be saturated with deuterium in the PISCES A device. Saturated and unsaturated samples will be loaded into the DIMES system. During H2 experiemnts, the strike point will be moved onto the DIMES system simulating an ELM strike. | ||
| Background: | Heat pulse experiments have begun in the PISCES A device utilizing laser heating in a divertor-like plasma background. Initial results indicate that the erosion of PFCs is enhanced as compared to heat pulse or plasma only tests. This enhanced erosion may be caused by self-sputtering of material that is ejected during the transient, ionized by the plasma near the surface and subsequently driven back to the surface. Gas retention in PFCs and ELM energy are currently indicated as the cause. | ||
| Resource Requirements: | A few shots during H2 experiments where the strikepoint can be moved onto the DIMES system. | ||
| Diagnostic Requirements: | High speed video of the DIMES system during the event. MDS of ablated material - C and W. | ||
| Analysis Requirements: | SEM imaging, TDS and mass loss analysis will be completed at UCSD PISCES lab. | ||
| Other Requirements: | -- | ||
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