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Effect of the shape of plasma density power spectra on ionospheric scintillations
Author(s) -
Serafim Philip E.
Publication year - 1980
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/rs015i005p01031
Subject(s) - scintillation , ionosphere , physics , amplitude , computational physics , interplanetary scintillation , spectral density , incoherent scatter , moment (physics) , scattering , electron density , wideband , optics , plasma , solar wind , geophysics , mathematics , classical mechanics , quantum mechanics , statistics , coronal mass ejection , detector
We present a systematic way to investigate the effect of the shape of an arbitrary power spectrum for the ionospheric plasma density on amplitude and phase scintillations through the study of appropriate wave number moments. These moments were found by following the random scattering of the wave inside the ionosphere and its diffraction into free space. We show that the inner and outer scales of the density spectrum are not sufficient for the description of several scintillation effects. We propose the necessary additional scales. For example, the distance at which amplitude scintillations become strong is not related to the inner scale of the plasma turbulence, as it had been assumed previously. In other words, it is not related to the variance 〈 k 2 〉. Instead, we find it to be related to the inner scale of the structure at the boundary between the ionosphere and free space. Equivalently, we prove it to be related to the moments 〈 k 〉 and 〈 k −1 〉. The differences may be very significant. As another example, we show that the near‐zone scintillation index depends on the moment 〈 k 3 〉. The theory so developed is applied to the case of a very general von Karman power spectrum. Some conclusions are drawn related to current research problems (Wideband satellite experiment, SHF scintillations).