DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 152: 2D Velocimetry of edge turbulence structures at the LH-transition | ||
| Name: | Dave Schlossberg ( |
Affiliation: | University of Wisconsin, Madison |
| Research Area: | Transport | Presentation time: | Requested | Co-Author(s): | G.R. McKee, M.W. Shafer, C. Holland, G. Tynan |
| Description: | Previous studies have revealed complex turbulence eddy structures at the time of the LH transition that reveal evidence of an increasing poloidal shear in the plasma edge. With the newly expanded BES array (to be implemented 2008), with up to 64 high-sensitivity channels, new explorations of turbulence physics will become accessible. By utilizing BES and other recently upgraded turbulence diagnostics, a more complete investigation of turbulence dynamics up to and at the time of the LH transition will be conducted. Possible H-mode trigger mechanisms (zonal flows/GAM), the role of turbulence flows and ExB shear in LH transition threshold power, comparison of flow shear and turbulence decorrelation rates, zonal flow behavior, nonlinear energy transfer, and spatial asymmetries in the eddy structures will all be investigated. | ||
| Experimental Approach/Plan: | Perform LH transition via neutral beam and possibly ECH. Obtain plasmas with fairly long ELM-free H-mode periods, and use the 64 upgraded high-sensitivity BES channels configured in an 8x8 array to examine turbulence behavior in the edge region (0.9 < r/a < 1.0) and also closer to the core (0.6 ~< r/a ~< 0.8). If necessary, alternate beam injection for CER/MSE measurements. Examine USN and LSN magnetic geometries for comparison of turbulence behavior at the transition time. | ||
| Background: | Perform LH transition via neutral beam and possibly ECH. Obtain plasmas with fairly long ELM-free H-mode periods, and use the 64 upgraded high-sensitivity BES channels configured in an 8x8 array to examine turbulence behavior in the edge region (0.9 < r/a < 1.0) and also closer to the core (0.6 ~< r/a ~< 0.8). If necessary, alternate beam injection for CER/MSE measurements. Examine USN and LSN magnetic geometries for comparison of turbulence behavior at the transition time. | ||
| Resource Requirements: | 150L&R, CER beams, other beams necessary for turbulence diagnostics, possibly ECH | ||
| Diagnostic Requirements: | BES, CER, other turbulence diagnostics | ||
| Analysis Requirements: | CERFIT for specific shots | ||
| Other Requirements: | -- | ||
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