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B. J. Rickett, Wm. A. Coles (University of Calif. San Diego)
It is well known that radio scattering in the interstellar plasma implies widespread inhomogeneities in density with a power law spatial spectrum and suggests a turbulent origin. Various recent observations have shown that the plasma turbulence is often highly anisotropic and is also clumpy. For example, locally enhanced anisotropic turbulence is responsible for the rapid variation in radio flux density in quasars B0405-385 and J1819+385. We will present new evidence from the spatial correlation in the scintillation of the two pulsars in the J0737-3039 system and from analysis of parabolic arcs in the scintillation of several nearby pulsars.
The results show that their scattering is caused by anisotropic plasma concentrated in relatively thin layers. In turn this suggests filamentary density structures aligned by the local magnetic field. Since the scattering would become isotropic if the irregulatities were uniformly distributed over many length scales of the magnetic field, we infer that the plasma turbulence is distributed intermittently – a conclusion also supported by the success of the screen model for pulsar scattering over paths up to a kiloparsec.
The author(s) of this abstract have provided an email address for comments about the abstract: bjrickett@ucsd.edu
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.