DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2013 EXPERIMENTAL CAMPAIGN
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| Title | 333: Far off-axis NBCD | ||
| Name: | Jin Myung Park parkjm@fusion.gat.com | Affiliation: | Oak Ridge National Lab |
| Research Area: | Steady State Heating and Current Drive | Presentation time: | Not requested |
| Co-Author(s): | ITPA Joint Experiment : | No | |
| Description: | Evaluate far off-axis NBCD physics; This is resubmission of 2012 proposal 92. | ITER IO Urgent Research Task : | No |
| Experimental Approach/Plan: | Use circular plasma and/or vertically shifted small plasmas with off-axis beams at maximum tilt angle. Drive off-axis NBCD with a peak location at rho > 0.7. Measure off-axis NBCD, beam ion density/energy distribution, and fast ion loss. | ||
| Background: | Driving current far off-axis ( rho > 0.7) is crucial in testing a potential of high bootstrap fraction, steady-state operation with a broad current profile for the future tokamak reactor beyond ITER. DIII-D experiment and modeling show that off-axis NBCD efficiency is as good as on-axis NBCD because the increased fraction of trapped electrons reduces the electron shielding of the injected ion current IN CONTRAST WITH electron current drive schemes where the trapping of electrons degrades the efficiency. This experiment is multi-purposes. For example, far off-axis NBI will allow a wide range of variations in or direct control of the rotation and radial electric field near the edge pedestal as well as fast ion orbit loss to test its impact on the edge pedestal structure. We may also have better chance to study the effects of microturbulence on fast ion confinement since the background turbulent fluctuation is in general larger when moving to outer radius region. | ||
| Resource Requirements: | All neutral beam sources with 150 beams at maximum tilt angle. All available gyrotrons to make variation of discharge conditions. | ||
| Diagnostic Requirements: | MSE, Neutrons, FIDA spectrometers & cameras, Core spectrometer | ||
| Analysis Requirements: | |||
| Other Requirements: | |||
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