DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 315: L-mode RMP thermal footprint | ||
| Name: | Michael J. Schaffer ( |
Affiliation: | General Atomics |
| Research Area: | Thermal Transport in the Plasma Boundary | Presentation time: | Not requested | Co-Author(s): | Ilon Joseph, Lasnier, Boedo, Moyer, others TBD |
| Description: | Test whether an L-mode plasma displays stronger signs of stochastic THERMAL transport when subjected to resonant magnetic perturbations (RMP) than H-mode plasmas. Such behavior might be expected, because an L-mode plasma rotates less rapidly and its edge is cooler and more resistive than an H-mode plasma. The most detectable sign of stochastic thermal transport is splitting of the THERMAL divertor footprint. Such a result would establish this as a good test plasma to study stochastic thermal transport across the separatrix of a diverted tokamak. | ||
| Experimental Approach/Plan: | Use an DND shape with its divertor biased away from the ion grad B drift in order to postpone L-H transition. The choice of upper or lower divertor will depend on diagnostic considerations. Run relatively low density to maximize power arriving at the divertor. | ||
| Background: | Split particle footprints have been associated with non axisymmetric resonant magnetic pertrubations (RMP) applied to H-mode plasmas, but the power footprint seems to rarely spread beyond a nearly axisymmetric circle. This may be evidence that the H-mode pedestal was not very stochastic, even when predicted to be so by vacuum field calculations. This might happen if the RMP field were e.g. electromagnetically shielded by plasma rotation. L-mode plasmas have cooler, more resistive edge plasmas that rotate less rapidly, so they are more likely to exhibit stochastic edges and, then, split divertor footprints. If so, this would be an interesting finding in its own right. It would also make available a good test plasma to study stochastic thermal transport across the separatrix and into a spirally broadened footprint. | ||
| Resource Requirements: | Positive Bt if experiment is run with lower divertor. | ||
| Diagnostic Requirements: | Divertor and SOL diagnostics. IR TV essential for divertor power profile measurements. | ||
| Analysis Requirements: | Trip3d | ||
| Other Requirements: | -- | ||
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