- By:
- Mckee, G. R.; Fonck, R.; Shafer, Morgan W; Uzon-Kaymak, I.
- Journal Name:
- Review of Scientific Instruments
- Page Number:
- 10
- Volume:
- 81
- Issue Number:
- 10
- Publication Date:
- March 22, 2012
- View DOI Listing:
- https://doi.org/10.1063/1.3495788
Abstract
Imaging of the size, shape, time-averaged, and time-resolved dynamics of long-wavelength density turbulence structures is accomplished with an expanded, high-sensitivity, wide-field beam emission spectroscopy (BES) diagnostic on DIII-D. A 64-channel BES system is configured with an 8 X 8 grid of discrete channels that image an approximately 7 X 9 cm region at the outboard midplane. The grid covers multiple correlation lengths and each channel shape matches the measured radial-poloidal correlation length asymmetry of turbulent eddies. The wide field 8 X 8 imaging capability allows for sampling of essentially the full two-dimensional spatial correlation function for typical plasma conditions. The sampled area can be radially scanned over 0.4 < r/a < 1, including the core ((n) over tilde /n < 1% ), pedestal, and scrape-off-layer. The resulting time-resolved visualizations of turbulence and flows provide critical data on turbulence dynamics.
