Visible Doppler Spectrometer for Edge Toroidal Rotation

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Visible Doppler Spectrometer for Edge Toroidal
Rotation
M.J. May, A. Graf, P. Beiersdorfer
The Alcator C-Mod Ideas Forum MIT Plasma Fusion
Center Dec. 2-3, 2004
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Edge Toroidal Rotation Measurements with Fast
Time Resolution
Present C-Mod Measurements
Toroidal rotation velocity measurements
3 chords through the plasma core with 20 ms
temporal resolution (x-ray). Single
chord edge view 50 ms temporal resolution
(UV-visible) Outside SOL via
magnetic probes
Proposed Measurement
Measure the toroidal rotation velocity via
Doppler shifted visible line emission at
several discrete spatial locations in the outer
half of the plasma with a high temporal
resolution ( 1 ms) Complement the present
visible spectrometer with faster time resolution
and more sensitive velocity measurements. Measu
rements potentially do not require a neutral beam.
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Spectrometer Capabilities
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Spectrometer
Side View
To Invessel Optics
Top View