THE APPLICATION OF A DIFFERENTIAL INTERFEROMETER TO AN AXIALLY SYMMETRIC ARC HEATED PLASMA.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING
Pagination or Media Count:
The refractive index of an atmospheric argon arc-heated plasma was measured with nearly monochromatic 5463 A light. The measurement was made with a differential interferometer which was compact and easy to set up and use. The basic components of the interferometer are two Wollaston prisms and a concave mirror. One prism separates plane polarized light into two diverging components to provide an optical path separation through the test object space. Optical inhomogeneities in the plasma object result in phase shifts between the separated rays. These phase shifts are doubled during the return passage of the rays upon reflection by the concave mirror. A second Wollaston prism, analyzer, and camera lens produce an interference fringe pattern which can be photographically recorded. The plasma induced phase shifts produce deflections of the nominally straight and parallel fringes. These deflections are proportional to the first derivative of the optical path through the plasma. Integration of the deflection curves was performed to yield the optical path shifts relative to air as a function of lateral distance.
- Plasma Physics and Magnetohydrodynamics