DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 325: Comparison of RWM stabilization physics in DIII-D and NSTX | ||
| Name: | Steven A. Sabbagh ( |
Affiliation: | Columbia University |
| Research Area: | RWM Physics | Presentation time: | Requested | Co-Author(s): | H. Reimerdes |
| Description: | Test theories of RWM stabilization physics, in particular the dependence on ion collisionality, relevance of Alfven frequency, and rotation profile (joint experiment with NSTX) | ||
| Experimental Approach/Plan: | Compare existing DIII-D and NSTX databases on RWM marginal stability to determine what data needs to be filled in for comparison of most recent results. Analogous scans determining RWM marginal stability vs. ion collisionality and plasma rotation will be needed in plasmas with similar proximity to passive conducting structure. Comparison of the DIII-D and NSTX databases between now and the time of the experiment may yield further desired scans in otherwise similar conditions.
Create plasmas with weak or no low frequency rotating MHD modes (especially n = 1). Variations of parameters should be conducted at fixed q. Change rotation profile by changing NBI mix. Operate at highest controllable elongation with good H-mode to best compare to NSTX. | ||
| Background: | A first-principles understanding of the physics of RWM stabilization is a critical, but elusive goal in RWM research. Various physical theories have been proposed for RWM stabilization, however, a unified physics model has not yet been found to explain results observed in all devices. A large database of results has been generated by DIII-D and NSTX, and initial joint experiments yielded some common understanding (H. Reimerdes, et al., PoP 13 (2006) 056107.) Experiments conducted on both DIII-D and NSTX since the original joint experiments have generated new questions and insights (e.g. influence of error field, rotation profile, and ion collisionality). The potential of RWM stabilization at low rotation via trapped particle precession drift resonance also suggests comparison between DIII-D and NSTX to examine experimental differences due to aspect ratio. | ||
| Resource Requirements: | Expect that full NBI power is needed, with maximum counter-NBI capability to best vary rotation profile. | ||
| Diagnostic Requirements: | Toroidal rotation profile measurement, MSE measurements | ||
| Analysis Requirements: | Most accurate EFIT reconstructions possible (Kinetic reconstructions with MSE, flux-isotherm constraint if available). | ||
| Other Requirements: | (present with other PPPL presentations) | ||
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