Strong scintillations in astrophysics. II. A theory of temporal broadening of pulses

A theory of temporal broadening of pulses propagating in a turbulent medium is developed, based on the Markov approximation discussed in Paper I. The theory may be applied to quite general turbulence spectra and to thin or thick turbulent regions. Since the basis of the theory is the wave equation, geometrical optics are not relied on, nor are assumptions made about the scattered angular spectrum. The observed smearing is found to be the combination of three effects which are termed the dispersion effect, the pure refractive effect, and the diffraction effect. The last of these dominates for typical pulsar parameters. The pulse shapes for both Gaussian and Kolmogorov turbulence spectra are calculated and it is shown how these scale with the various turbulence parameters