Scrape-off layer reflectometer for Alcator C-Mod
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States)
A two-frequency x-mode reflectometer operating from 100 to 146 GHz is deployed on Alcator C-Mod to measure the density profile and fluctuations in the scrape-off layer (SOL) immediately in front of the new J-port ICRF antenna and the new C-port lower hybrid launcher. The reflectometer covers densities from 10{sup 16} to 10{sup 20} m{sup -3} at 5-5.4 T. To provide the greatest flexibility and capability to deal with density fluctuations approaching 100% peak-to-peak in the SOL, both full-phase and differential-phase measurement capabilities with sweep speeds of {approx}10 {mu}s to >1 ms are implemented. The differential-phase measurement uses a difference frequency of 500 MHz, corresponding to cutoff layer separations ranging from about 0.1 to 1 mm. The reflectometer has six sets of launchers: three on the ICRF antenna and three on the lower hybrid launcher. Both the ICRF antenna and the lower hybrid launcher incorporate reflectometer antennas at their top, bottom, and midplane locations.
- OSTI ID:
- 21266603
- Journal Information:
- Review of Scientific Instruments, Vol. 79, Issue 10; Conference: HTPD08: 17. topical conference on high-temperature plasma diagnostics, Albuquerque, NM (United States), 11-15 May 2008; Other Information: DOI: 10.1063/1.2966460; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
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