Lightning Flares in the Cloud Layer of Venus Detected in the Near-Infrared Range

Abstract

Venus was the first of the planets of the Solar System in the atmosphere of which electrical phenomena similar to lightning in the Earth’s atmosphere were discovered. Electrical discharges (lightning in the atmosphere of Venus) were discovered in 1978 in the Venera-12, -11, and Pioneer Venus missions, based on their electromagnetic radiation. The paradox, however, was that the search for optical flares remained unsuccessful for the past 40 years. In 2015, the Akatsuki spacecraft of the Japan Aerospace Exploration Agency was launched into orbit Venus satellite. It was designed to search for lightning and other studies of the meteorology of Venus by recording radiation in selected spectral ranges. In 2016, the Akatsuki orbiter successfully performed detailed observations of Venus in the near-infrared range in the “transparency windows” of the planet’s atmosphere, as well as in the ultraviolet and other ranges. The article presents the results of an alternative search for and successful detection of lightning flashes according to the Akatsuki project, but not in the ultraviolet or visible ranges, but in the near-IR range. A comparison of the results of calculations based on models of terrestrial lightning with the results of measurements made by the IR2 camera of the Akatsuki mission on Venus at a wavelength of 2.26 μm shows a close agreement between the experimental and calculated data.