Characteristic Features of V0 Layer in the Venus Ionosphere as Observed by the Akatsuki Orbiter: Evidence for Its Presence During the Local Noon and Post‐Sunset Conditions

Abstract

AbstractCharacteristic features of the Venus ionosphere below the V1 base, named as V0 layer, have been studied using the Radio Science payload onboard Akatsuki orbiter. An ionospheric layer below the V1 base is known to be present in the Venus ionosphere but found to be geographically localized, seen mostly during the daytime between 55 and 90° solar zenith angle (SZA). We, for the first time, show its presence at different latitudes and SZA, including near the equator during the local noon and post‐sunset hours. The maximum density of this layer was ∼4 × 1010 m−3 at the altitude range of 110 ± 4 km. In the absence of in‐situ measurements, it's difficult to comment on the origin but the presence of such layers during post‐sunset hours suggests their meteoric origin as the observed altitudes are consistent with the height range predicted by the meteor models. Other possible sources of such layers are also discussed.