DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 19: Use DIII-D pumping capability to separate density and temperature in Rice's scaling | ||
| Name: | John Degrassie ( |
Affiliation: | General Atomics |
| Research Area: | Rotation Physics | Presentation time: | Not requested | Co-Author(s): | W.Solomon, J.Rice, K. Burrell |
| Description: | *TBD is the best approach to obtaining companion discharges with and without pumping. Hopefully the straightforward approach of having shots with the pump on and then off will work. Previously we attempted moving the strike-point slightly but we still needed pump-off shots, and given the limited one-day time we never optimized the pumping location. Pump on/off should allow time to fix the best pumping location.
*We need companion discharges at the same stored energy (beta) but with different densities, at the same Ip with the intrinsic velocity profiles measured. *We want the above set at a) At least two values of stored energy and b) At least two values of Ip. | ||
| Experimental Approach/Plan: | We will use a DIII-D shape that gives the best chance for density control in ELMing H-modes with pumping, presumably an appropriate Single Null shape. We need velocity measurements at several density values, with nT constant. This will no doubt involve slight repositioning of the strike point. We will also need companion shots in the same x-point configuration with the pump off. | ||
| Background: | Rice's engineering scaling for intrinsic rotation shows that the toroidal velocity scales as W/Ip. The scatter in the international database does not allow one to surmise whether or not density and temperature enter W, the stored energy, on an equal footing. We can use the DIII-D pumping capability to vary the density in ELMing H-mode, adjust the mix of ECH and potentially near-balanced NBI to keep the stored energy constant and measure the intrinsic velocity. A definitive experiment will go along way in limiting potential theoretical explanations. | ||
| Resource Requirements: | Same as proposal 14. Want to do near-balanced beam intrinsic rotation measurements in the back of these discharges. | ||
| Diagnostic Requirements: | standard for intrinsic rotation | ||
| Analysis Requirements: | -- | ||
| Other Requirements: | -- | ||
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