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Session 57 - Interstellar Scattering and Scintillation as Tools in Radio Astronomy.
Display session, Wednesday, June 10
Atlas Ballroom,
We have recorded ``Giant'' radio pulses from the Crab Nebula pulsar at the VLA for several years at a variety of frequencies between 0.33 and 8.4 GHz, and occasionally at two frequencies simultaneously. Our time resolution (10 ns) allows us to study the pulses with unprecedented detail. At low frequencies the pulses are broadened by interstellar scattering; we find that the scattering parameters are time variable. At the highest frequencies we find pulse broadening times that scale with frequency more slowly than \lambda^4, and we find single pulse periods in which pulse components show different scattering broadening. The high-frequency broadening may be intrinsic to the pulsar, either through the emission mechanism or by scattering in the pulsar magnetosphere.