SIMULATION AND PROTOTYPE CONSTRUCTION. PROJECT CANTALOUPE.
REPUBLIC AVIATION CORP FARMINGDALE N Y
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A theta-pinch apparatus specifically designed for the purpose has been used to study Rayleigh-Taylor instabilities at a plasma-magnetic field interface. Special features include preionization, a pulse-shaping network, and a provision for transverse as well as axial photography. A constant magnetic field results in a constant velocity radial compression, in good agreement with snowplow theory. In this case, as expected, no surface instabilities are observed. A sinusoidal compression field, however, results in instabilities whose wavelength and growth rate are measured. Theoretical dispersion relations for finite electrical conductivity and for finite viscosity are derived. In addition, the mode of maximum instability is determined. These relations are compared with the expeerimental results. The observed wavelength assumed to be the wavelength of maximum instability and its growth rate are in agreement with the assumption that the effect of viscosity must be retained in the dispersion relation. The dispersion relation in the present case is independent of the electrical conductivity. While previous investigators have attempted to correlate observed wavelengths with finite electrical conductivity, this is shown here to be unwarranted. Author