Pulsar scintillations: frequency crosscorrelation and effects of finite bandwidth.
Abstract
For a medium containing electron density fluctuations with a Gaussian spectrum of irregularities, a comparison is given of results previously obtained from numerical integration of the secondorder moment equation used to describe interstellar scintillation of pulsar signals and of results following from the exact analytical solution of the equation. It is shown that the numerical integration results are in error  typically by 10 to 20 percent. The error is particularly serious for the following reason. In the Gaussian case, the error is quantifiable, since an exact analytical solution exists. In the case of a Kolmogorov spectrum of irregularities (which lacks an analytical solution), there is no reason to believe that similar errors are not present also in the numerical integration of the equivalent equation. A comparison of theoretical predictions of the exact analytical solution with observed intensity correlations for PSR 083345 showed that the observed shape of the bandwidthsmeared autocorrelation function differs markedly from the shape predicted on the basis of the assumption that intensity correlation is accurately represented by unity plus the square of the modulus of correlation of twowave amplitudes, and that the electron density irregularities have a Gaussian spectrum.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 October 1979
 DOI:
 10.1093/mnras/189.2.137
 Bibcode:
 1979MNRAS.189..137L
 Keywords:

 Correlation Detection;
 Pulsars;
 Radio Astronomy;
 Scintillation;
 Variations;
 Astronomical Models;
 Electron Density (Concentration);
 Fluctuation Theory;
 Graphs (Charts);
 Mathematical Models;
 Normal Density Functions;
 Spectrum Analysis;
 Astrophysics;
 Pulsars:Scintillations