CO2 laser scintillation interferometer for the measurement of density fluctuations in plasma confinement devices

Nazikian, R.; Sharp, L. E.
November 1987
Review of Scientific Instruments;Nov87, Vol. 58 Issue 11, p2086
Academic Journal
Density fluctuations in magnetically confined plasmas have been measured from the phase scintillations impressed onto a 10.6-μm wavelength laser beam probe, using a Mach–Zender interferometer operating in the optical near field. By careful design, the effects of vibration and air-borne sound waves, which limit the instrument’s sensitivity, have been reduced to a level such that the minimum detectable signal is 10-6 rad in the frequency range 10 kHz–1 MHz, corresponding to a plasma density fluctuation level (δN/N) of 10-4.


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