DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 462: Modulated ECH to study pedestal electron thermal transport in ELM-stabilized discharges via RMP | ||
| Name: | Richard Groebner ( |
Affiliation: | General Atomics |
| Research Area: | ELM Control & Pedestal Physics | Presentation time: | Not requested | Co-Author(s): | -- |
| Description: | Determine if electron thermal transport is increased in ELM-stabilized discharges, via application of RMP, as opposed to standard ELM-ing discharges without the application of RMP. | ||
| Experimental Approach/Plan: | Apply modulated ECH at top of pedestal in ELMing and ELM-suppressed discharges (via RMP). Observe the temporal response of electron temperature at the top of the pedestal from ECE and in the pedestal from SXR. Determine if temperature decays more quickly after end of an ECH pulse with RMP applied as opposed to no RMP. | ||
| Background: | As is well known, Resonant Magnetic Perturbations (RMP) in DIII-D have been used to stabilize ELMs. It is quite clear that the perturbed edge magnetic fields lead to enhancements of particle transport. In turn, the increased particle transport leads to a reduction of the pedestal density and this allows the pedestal to remain within an MHD-stable zone, as computed with ELITE. In contrast, the Te profile is not much changed by the application of the RMP. This is an outstanding mystery because it is expected that edge perturbed magnetic fields would allow electrons to escape from the plasma and thus to reduct the electron temperature. We evidently are not observing this. However, the electron transport is difficult to study and is not well studied for these discharges. We propose to use techniques of modulated transport to determine if the RMP degrades the electron thermal transport relative to discharges without an RMP. | ||
| Resource Requirements: | 5 neutral beam sources
4 ECH gyrotrons, aimed at plasma edge | ||
| Diagnostic Requirements: | TS, CER, CO2, ECE, SXR | ||
| Analysis Requirements: | -- | ||
| Other Requirements: | -- | ||
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