DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 299: QH-mode studies as a function of edge rotation | ||
| Name: | Keith Burrell ( |
Affiliation: | General Atomics |
| Research Area: | ELM Control & Pedestal Physics | Presentation time: | Not requested | Co-Author(s): | W.M. Solomon, M.E. Fenstermacher, P. Gohil, C.J. Lasnier,T.H. Osborne, P.B. Snyder |
| Description: | Determine whether the QH-mode can be achieved with balanced or even
some co-injection. Investigate effects of edge rotation on QH-mode plasmas with emphasis on changes in EHO-induced particle transport. | ||
| Experimental Approach/Plan: | Start the experiment in QH-mode plasmas similar to 128502. Utilize
RMW feedback to null out the remaining intrinsic error field. Investigate this QH-mode as rotation is made more and more co. Important questions are the nature of the EHO and its effect on particle transport. | ||
| Background: | During the 2006 and 2007 campaigns, we made significant progress in
producing QH-mode plasmas with reduced counter rotation. This was achieved by optimizing the plasma shape for peeling-ballooning mode stability and by reducing the intrinsic error fields. The latter is the key to preventing locked modes at low toroidal rotation. In moderate beta QH-mode plasmas, we have seen error field amplification on the ESLD detectors. This effect indicates that we still do not have optimal error field correction; however, this effect is also what is needed to use the RWM feedback system to null out the remaining intrinsic error fields. Unfortunately, we did not have time to apply this RWM feedback technique in 2007. We have also seen that the particle transport due to the EHO decreases as the magnitude of the toroidal rotation decreases. This leads to higher density and higher pedestal pressures, which in general are destabilizing to the peeling ballooning modes. However, using the optimized high-triangularity, double-null shape provided enough stability margin that we remained in QH-mode. | ||
| Resource Requirements: | Reverse Ip. 7 NBI sources | ||
| Diagnostic Requirements: | -- | ||
| Analysis Requirements: | -- | ||
| Other Requirements: | -- | ||
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