Comparison of Ionospheric Scintillation Parameters of Powerful Radio Sources at Decameter Wavelengths with Indices of Solar and Geomagnetic Activity

Abstract

The ionospheric scintillation parameters were obtained from observations of the powerful radio sources at the frequencies 20 and 25 MHz: index s₄, characteristic time t and index of the spectrum slope p. These values were compared with indices of solar (flux at the wavelength 10.7 sm P₁₀ ) and
geomagnetic (Ap index) activities. The dependence of the ionospheric scintillation index on mentioned parameters was investigated for different time intervals (from several days to several years). A strong enough seasonal-daily dependence of the scintillation index makes difficult the data consideration for intervals less than year. Thereat, the dependencies obtained for yearly mean values proved to be most reliable. In particular, the yearly mean values of the scintillation characteristic time were found to correlate
with the values of flux P₁₀. However, no clear interconnection between scintillation parameters and geomagnetic activity index was found.