DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 375: Test of causality: mode rotation vs. plasma rotation | ||
| Name: | Francesco Volpe ( |
Affiliation: | ORAU |
| Research Area: | Rotation Physics | Presentation time: | Requested | Co-Author(s): | -- |
| Description: | In locking at low rotation, mode slows down the plasma? or plasma slows the mode down? And in rotational mitigation, it is well-known that the rotating plasma drags the mode, but can torque imparted to the mode drag the plasma? | ||
| Experimental Approach/Plan: | Use co/ctr NBI mixture to control plasma rotation, I-coils to control mode rotation, CER to measure plasma rotation and Mirnov spectrograms (newspec) to measure mode rotation. Then use an approach similar to K.Burrell's H-mode studies (PoP 1999): modulate the mode (plasma) rotation and measure the delay of the plasma (mode) response. Hysteresis curves will be obtained. | ||
| Background: | NTMs are approximately "frozen" in the plasma and spinning the latter (by momentum injection with NBI) also spins the former. Various proposals and some experimental evidence exists, suggesting that the opposite is also true, i.e. that torque imparted to the mode also spins the plasma. If confirmed, plasma rotation (and not just mode rotation) would represent one more application for internal coils in devices with low NBI momentum injection like ITER. Similar considerations apply to plasma and mode braking, and how they affect each other. For example, rotating modes are known to lock even in rotating plasmas which keep rotating. On the other hand, slow plasma rotation encourages mode locking. | ||
| Resource Requirements: | -- | ||
| Diagnostic Requirements: | -- | ||
| Analysis Requirements: | -- | ||
| Other Requirements: | -- | ||
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