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Strong scintillations in astrophysics. I - The Markov approximation, its validity and application to angular broadeningThe Markov approximation to the propagation of waves in an extended, irregular medium is discussed in an astrophysical context. A new derivation is presented which is simple and which shows that the assumption of Gaussian statistics used by previous authors is irrelevant. We discuss the relevance of the approximation and show that it may apply in many situations of interest, including interstellar scintillations of pulsar signals. The approximation does not require the assumption of weak scattering or Gaussian correlation functions. The Markov equation for the angular spectrum is particularly simple, and solutions are discussed for typical turbulence spectra. It is found that the equation for the angular spectrum is very nearly that used by previous authors, and the present discussion shows that these results are much more general than previously thought. A possible observational test for distinguishing between Gaussian and power-law interstellar density spectra is discussed.
Document ID
19750043143
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Lee, L. C.
Jokipii, J. R.
(California Institute of Technology Pasadena, Calif., United States)
Date Acquired
August 8, 2013
Publication Date
March 15, 1975
Publication Information
Publication: Astrophysical Journal
Volume: 196
Subject Category
Astrophysics
Accession Number
75A27215
Funding Number(s)
CONTRACT_GRANT: NGR-05-002-160
CONTRACT_GRANT: NSF GP-39507
Distribution Limits
Public
Copyright
Other

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