Peculiarity of continuum emission from upper corona of the sun at decameter wavelengths

Abstract

The results of investigations of the quiet Sun radio emission at decameter wavelengths are suggested. The observations have been made with the URAN-2 antenna array in summer seasons of 2008-2009 at 20 and 25 MHz within 250 kHz bandwidth together with the UTR-2 radio telescope in the summerautumn period of 2010 at 16.5 to 33.0 MHz in the mode of onedimensional heliograph. The average values of flux density of the quiet Sun corona according to URAN-2 measurements is equal to 860 Jy at 25 MHz and 710 Jy at 20 MHz. The values of integral flux density from UTR-2 measurements for these frequencies are 950 and 800 Jy, respectively. The URAN-2 and UTR-2 measured data as respects the spectral index within 16.5 ÷ 200 MHz have shown it to be the same and equal to −2.1±0.1. The angular sizes of equatorial diameter of solar corona have been determined from the UTR-2 observations. The results yielded are in good agreement with the values known for the continuum radiation from the solar corona at higher frequencies. The efficiency of simultaneous application of different geographically spaced radiotelescopes with coincident frequency range is shown, too.