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Astrophysics and Space Science

, Volume 79, Issue 1, pp 165–180 | Cite as

Scintillations of cosmic radio sources in the decametre waveband

I. Spectra of scintillations due to ionospheric and interplanetary plasma fluctuations and the possibility of their separation
  • V. P. Bovkoon
  • I. N. Zhouck
Article

Abstract

The effect of fluctuations of the interplanetary plasma and the ionosphere upon the scintillation spectra of radio sources at decametre waves is considered with due regard for the finite antenna aperture, fluctuation anisotropy, and the direction of their drift in space. It has been shown that scintillation due to interplanetary plasma (IPP), can be reliably separated from the ionospheric scintillation background at decametre wavelengths.

For elongations between 90° to 150°, the IPP scintillation power spectrum observed in the 12.6–25 MHz waveband is of a power law form with the index 3.1±0.6, which is in close agreement with the values known for smaller elongations. The solar wind velocity projection orthogonal to the line of sight is estimated for elongations about 110° and has been found to be 300±80 km s−1. As in the case of smaller elongations, the velocity dispersion is significant.

At night, wideband spectra of ionospheric scintillations are observed in the decametre band, with the breaking point at approximately 0.01 Hz in the 12 m band, and narrow-band spectra whose cut-off frequency is below 0.01 Hz. The power spectrum of ionospheric scintillations is of a power-law form with the index 3.4±0.5. In some cases steeper spectra are observed.

Keywords

Solar Wind Radio Source Solar Wind Velocity Ionospheric Scintillation Antenna Aperture 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© D. Reidel Publishing Co. 1981

Authors and Affiliations

  • V. P. Bovkoon
    • 1
  • I. N. Zhouck
    • 1
  1. 1.Division of Radio-Astronomy at the Institute of Radiophysics and ElectronicsAcademy of Sciences of the Ukrainian S.S.R.KharkovUSSR

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