A High-Speed Optical Diagnostic that uses Interference Filters to Measure Doppler Shifts
Paul, S.F.
Cates, C.
Mauel, M.
Maurer, D.
Navratil, G.
Shilov, M.
United States. Department of Energy. Office of Science.
Princeton University. Plasma Physics Laboratory.
2004-08-09
English
A high-speed, non-invasive velocity diagnostic has been developed for measuring plasma rotation. The Doppler shift is determined by employing two detectors that view line emission from the identical volume of plasma. Each detector views through an interference filter having a passband that varies linearly with wavelength. One detector views the plasma through a filter whose passband has a negative slope and the second detector views through one with a positive slope. Because each channel views the same volume of plasma, the ratio of the amplitudes is not sensitive to variations in plasma emission. With suitable knowledge of the filter characteristics and the relative gain, the Doppler shift is readily obtained in real time from the ratio of two channels without needing a low throughput spectrometer. The systematic errors--arising from temperature drifts, stability, and frequency response of the detectors and amplifiers, interference filter linearity, and ability to thoroughly homogenize the light from the fiber bundle--can be characterized well enough to obtain velocity data with + or - 1 km/sec with a time resolution of 0.3 msec.
Time Resolution
Amplitudes
Fibers
70 Plasma Physics And Fusion Technology
Diagnostics
Velocity Diagnostics
Doppler Effect
Stability
Amplifiers
Velocity
Rotation
Plasma
Other Information: PBD: 9 Aug 2004
Report
3.2 MB pages
Text
rep-no: PPPL-3994
grantno: AC02-76CH03073
doi: 10.2172/828607
osti: 828607
https://digital.library.unt.edu/ark:/67531/metadc786058/
ark: ark:/67531/metadc786058