DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 260: Poloidal spin up of plasma using off-axis neutral beam injection | ||
| Name: | Wayne M. Solomon ( |
Affiliation: | Princeton Plasma Physics Laboratory |
| Research Area: | Transport | Presentation time: | Not requested | Co-Author(s): | K.H. Burrell |
| Description: | The idea is to displace the plasma vertically to significant z values (ideally up to +/-20 cm), such that the neutral beams can impart a poloidal torque to the plasma, and drive poloidal rotation. Such a displaced plasma might also be used to investigate off-axis current drive. | ||
| Experimental Approach/Plan: | The measurement must first be performed with the plasma centered on the midplane. This is necessary to utilize vertical chords viewing the magnetic axis. Such chords are important for determining the effective lifetime of the charge exchange state, which is needed for proper treatment of the atomic physics corrections to the measurements. The plasma can then be incrementally displaced vertically to introduce poloidal torque. Since we will lose the on-axis vertical chords, the previously determined lifetime will be used throughout the experiment. By shifting both upwards and downwards, we can evaluate whether the poloidal rotation flips sign as might be expected. Although poloidal rotation is in general heavily damped, driving poloidal rotation of the order of 10-20 km/s would be a significant source of Er even under typical conditions. Furthermore, if we run balanced type injection such that the toroidal rotation is small, then the Er can be dominated by the poloidal rotation contribution. A key question will be whether the resulting ExB shearing rate is sufficient in these conditions to achieve turbulence suppression. | ||
| Background: | Anomalously large poloidal rotation of order 5-10 km/s has been observed in QH-mode and ELM-suppressed H-mode plasmas. Adding direct neutral beam drive may allow us to access larger poloidal rotation regimes. | ||
| Resource Requirements: | Machine Time: 1 day Experiment
Number of neutral beam sources: 5 | ||
| Diagnostic Requirements: | CER | ||
| Analysis Requirements: | -- | ||
| Other Requirements: | -- | ||
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