DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2013 EXPERIMENTAL CAMPAIGN
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| Title | 19: Effect of n=1 applied and error fields on n=3 RMP ELM suppression | ||
| Name: | John deGrassie degrassie@fusion.gat.com | Affiliation: | General Atomics |
| Research Area: | ELM Control | Presentation time: | Not requested |
| Co-Author(s): | Carlos Paz-Soldan, Matt Lanctot | ITPA Joint Experiment : | No |
| Description: | This experiment will investigate the effect of error fields on the q95 windows in standard shape LSN n=3 RMP ELM suppression. Controlled scans and variations of the added n=1 field will be tested by varying the level of C-coil error correction, and adding n=1 field perturbations to the C-coils with varying amplitude and toroidal phase. The goal is to determine to what extent, if any, the n=1 field (background) is determining the standard n=3 ELM suppression q95 windows. | ITER IO Urgent Research Task : | No |
| Experimental Approach/Plan: | A reference n=3 RMP ELM suppression condition will be established. First, an added n=1 rotating perturbation will be added to the C-coils and any effect on an otherwise clean window of ELM suppression will be measured. The perturbation amplitude will be raised until locking, or the return of ELMs takes place. The results will guide the amplitude and phase of the n=1 parameter search to be conducted. Ip ramps will be used to look for variations in q95 suppression windows. | ||
| Background: | * As yet, no predictive model tells us where the windows of RMP ELM suppression will take place in DIII-D. Some hypotheses are that a) a resonant surface must be located at the ??correct? place relative to the electron pressure pedestal, b) that perhaps n=1 error fields are in some way giving preference to q95 windows approaching q95 ~ 3/1, c) that the kink response of the plasma is favoring the low q95 region for suppression windows.
* This experiment seeks to investigate the n=1 error hypothesis. | ||
| Resource Requirements: | One day. Standard for RMP n=3 ELM suppression. ECH available | ||
| Diagnostic Requirements: | -- | ||
| Analysis Requirements: | -- | ||
| Other Requirements: | -- | ||
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