DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 353: Stabilization of giant sawteeth through the reduction of the fast particle pressure gradient. | ||
| Name: | Gerrit J. Kramer ( |
Affiliation: | Princeton Plasma Physics Laboratory |
| Research Area: | Stability | Presentation time: | Not requested | Co-Author(s): | G.J. Kramer, R. Nazikian, M. van Zeeland, B, Heidbrink, N.N. Gorelenkov |
| Description: | Giant sawteeth are stabilized by the pressure of fast particles inside the
q=1 surface. Gradients in that population can excite core-localized Alfven eigenmodes (C-TAE) (otherwise known as energetic particle modes). It has been shown that these C-TAEs can transport fast ions from inside to outside the q=1 surface which results in a reduction of the fast-ion pressure to below a point where the the sawtooth is stabilized and a giant sawtooth is triggered. | ||
| Experimental Approach/Plan: | We propose to modify the the fast-particle pressure gradient inside the
q=1 surface during the sawtooth stabilization period by varying the toroidal magnetic field in such a way that the power from the ICRF is spread more evenly inside the q=1 surface. This reduces the fast-ion pressure gradients which drive the C-TAEs. A variation of about 0.05 Tesla is needed on a 100-500 ms time scale. | ||
| Background: | -- | ||
| Resource Requirements: | -- | ||
| Diagnostic Requirements: | Studying the behavior of the fast ion population together with the
Alfven eigenmode activity is crucial for this experiment and DIIID is the only place that has the diagnostic capability to do this. | ||
| Analysis Requirements: | -- | ||
| Other Requirements: | -- | ||
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