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M. L. Rudolph, K. A. Allen (Oberlin), T. J. W. Lazio (NRL), D. R. Stinebring (Oberlin)
Multiple imaging of pulsars by AU-scale structures results in (low-level) organized patterns in pulsar dynamic spectra and ``scintillation arcs'' in secondary spectra. Detailed new observations of scintillation arcs have been made in the past several years (e.~g. Hill et al. 2003 ApJ, 599, 457), showing evidence for scattering from stochastic {\em and} deterministic structures in the ionized ISM. Progress requires a comparison between observations and simulations of radio wave propagation through a random medium. We have developed a numerical simulation that does this, incorporating a power-law inhomogeneity spectrum with inner and outer scale cutoffs. Currently the simulation places the scattering in a single thin screen, but we plan to allow a more general distribution of scattering material along the line of sight. The simulation uses two spatial dimensions (transverse to the line of sight) and a radio frequency dimension. We present preliminary results of this modeling effort.
This work was supported by a grant from the National Science Foundation (PI: DRS). Basic research in radio astronomy at the NRL is supported by the Office of the Naval Research.
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.