CO/sub 2/ laser interferometer array for Big Dee

Conference · Sat Sep 01 00:00:00 EDT 1984

OSTI ID:6346945

Fairbanks, E S

A twelve channel interferometer array is planned for obtaining electron density profiles on Big Dee. Each channel consists of coaxial CO/sub 2/ and HeNe laser beams. The reference beam is formed by splitting off half of the laser power at each wavelength by using acousto-optic modulators which introduce a 40 MHz frequency shift in the reference beam. The detected interference signals from room temperature visible and IR detectors are mixed with the 40 MHz drive for the acousto-optic cells. The quadrature mixer signals result in phase information due to vibration and phase velocity variation in the plasma. Simultaneous solution of the two equations describing the phase shift at the two wavelengths yields the phase shift due only to the plasma effects. The arithmetic operations will be performed digitally in real time by a dedicated microprocessor in each channel. The execution speed of the microprocessor is expected to be sufficent for measuring line integral density in the presence of vibrations of 1 mm amplitude at 1 Hz or 10 ..mu..m amplitude at 100 Hz. Phase resolution for each channel is 2..pi../64 and time between samples is 25 ..mu..sec. Density profiles are derived from chordal line integral density data by computer tomography.

• Research Organization: GA Technologies, Inc., San Diego, CA (USA)
• DOE Contract Number: AT03-84ER51044
• OSTI ID: 6346945
• Report Number(s): GA-A-17708; CONF-840922-16; ON: DE85001718
• Resource Relation: Conference: 5. APS topical conference on high temperature plasma diagnostics, Tahoe City, CA, USA, 16 Sep 1984
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
DOUBLET REACTORS
PLASMA DIAGNOSTICS
INTERFEROMETERS
CARBON DIOXIDE LASERS
GAS LASERS
HELIUM
LASER RADIATION
NEON
ELECTROMAGNETIC RADIATION
ELEMENTS
FLUIDS
GASES
LASERS
MEASURING INSTRUMENTS
NONMETALS
RADIATIONS
RARE GASES
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS
700102* - Fusion Energy- Plasma Research- Diagnostics