Solar bursts as can be observed from the lunar farside with a single antenna at very low frequencies

Abstract

Earth-based observations are complicated by the opacity of Earth's ionosphere at very low frequencies and strong man-made radio frequency interference. This explains long-standing interest in building a low-frequency radio telescope on the farside of the Moon. Experience from ground-based observations near the ionospheric cutoff in dealing with the interference, ionosphere, and wide-field imaging/dynamic range problems provides crucial information for future radio-astronomic experiments on the Moon. In this purpose, we observed nonintensive solar bursts on the example of solar drift pairs (DPs) at decameter-meter wavelengths with large and small arrays as well as by a single-crossed active dipole. We used the large Ukrainian radio telescope UTR-2, the URAN-2 array, a subarray of the giant Ukrainian radio telescope (GURT), and a single-crossed active dipole to get the spectral properties of radio bursts in the frequency range of 8-80 MHz during solar observations on July 12, 2017. Statistical analysis of upper and lower frequencies, at which DPs are recorded, shows that the occurrence of forward DPs is more preferable at lower frequencies of the decameter range of observations in comparison with reverse DPs generated more likely in meter wavelengths. We conclude that DPs can be detected not only by antenna arrays, but even by a single-crossed active dipole. Thus, the latter antenna has good potential for future low-frequency radio telescopes on the Moon.

The first detection of the solar U+III association with an antenna prototype for the future lunar observatory

“…The construction of a large scale radio array is not an easy task even on Earth, and on the other planets and moons this task is a major challenge for humanity to build scientific instruments in extreme conditions. The Ukrainian program of lunar explorations by spacecrafts has been suggested by Shkuratov et al (2019), and perspective steps to solar studies with the help of radio observations on the lunar farside were considered by Stanislavsky et al (2018). Advancing this program as applied to radio astronomy purposes, we produced an antenna prototype for the future lunar telescope at ultra-long wavelengths.…”

The first detection of the solar U+III association with an antenna prototype for the future lunar observatory

“…The making of a large scale radio array is not an easy task even on Earth, and on the other planets and moons this task is a challenge for mankind to build scientific instruments in extremal conditions. The Ukrainian program of lunar explorations by spacecrafts has been suggested by Shkuratov et al (2019), and perspective steps to solar studies with help of radio observations on the lunar far side were considered by Stanislavsky et al (2018). Advancing this program as applied to radio astronomy purposes, we produced an antenna prototype for the future lunar telescope at ultra long wavelengths.…”