DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 58: ECCD in High Beta Poloidal Plasmas | ||
| Name: | C. Craig Petty ( |
Affiliation: | General Atomics |
| Research Area: | Heating & Current Drive | Presentation time: | Not requested | Co-Author(s): | P. A. Politzer, R. Prater, M. Choi |
| Description: | Use off-axis ECCD for current profile control in high beta poloidal plasmas with large bootstrap current fraction. Also test the effect of beta poloidal on the ECCD efficiency. | ||
| Experimental Approach/Plan: | (1) Establish high beta poloidal plasmas with high bootstrap current using two gyrotrons for central heating. (2) Inject ECCD off-axis (4 gyrotrons) and measure the effect on the current profile evolution. Scan the resonance location radially, and scan the toroidal injection angle to compare the effects of co and counter ECCD. (3) Use an open loop method of adjusting the ECCD power and location to give the optimal current profile for the high bootstrap current experiments. (4) Keeping ne and Te fixed, raise the plasma current to lower beta poloidal. Measure the effect on the ECCD efficiency at various radial locations. | ||
| Background: | Demonstrating current profile control is an important next step for showing the utility of the ECCD system on DIII-D. High beta poloidal plasmas are a good candidate for this since they have little ohmic current (thus the back EMF effects are small). Current profile control may be a benefit to optimizing the high bootstrap current experiments. Furthermore, we can use these plasmas to extend our ECCD database by comparing the ECCD efficiency in plasmas with the same ne*Te but different Ip. This will be an important test of the effect of beta poloidal on the ECCD efficiency (high beta poloidal is expected to reduce trapping effects and increase the current drive efficiency). | ||
| Resource Requirements: | NBI: At least 4 sources.
EC: Minimum 5 gyrotrons. | ||
| Diagnostic Requirements: | MSE is critical. | ||
| Analysis Requirements: | -- | ||
| Other Requirements: | -- | ||
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