Revisiting the structure function of PSR B0950+08 scintillations

The observational structure function of the scintillations of the radio pulsar PSR B0950+08 was fitted, a decade ago, with a power law with index 1 +/- 0.05. This was interpreted as an appreciable deviation from the commonly observed index of 5/3, expected for Kolmogorov turbulence. In this paper, it is suggested that the observations are consistent with a Kolmogorov turbulence and that the apparent deviation is due to a turbulent region with an effective depth, which is comparable to the observed lateral scales on the plane of the sky, spanned by the pulsar beam. Alternatively, the fitted index of 1 is consistent with an underlying compressive turbulence and an even smaller depth. In the first interpretation, the depth is (5.5 +/- 1.8) x 10(8) cm. In the second one, the depth is less than or similar to 4 x 10(7) cm. These estimates lend support for the existence of extremely thin, ionized scattering screens in the local interstellar cloud that have been proposed a decade ago.

Automated summary

This paper examines the observational structure function of the scintillations of the radio pulsar PSR B0950+08 and proposes that the deviations observed are consistent with both Kolmogorov turbulence and compressive turbulence, which differ in terms of the depth of turbulent regions. The estimates support the presence of extremely thin, ionized scattering screens in the local interstellar cloud, as proposed a decade ago.