Venus lightning: Estimation of charge and dimensions of charge regions for lightning initiation

Abstract

The occurrence of Venusian lightning must be preceded by electrification of particles in Venusian clouds and separation of these charged particles to form distinct charged regions. In this work, we estimate the minimum required charge and the dimensions of these charge regions in order for lightning to occur. The expected streamer speed in Venusian middle clouds is on the order of 105–106 m/s. The charged region in Venus's middle clouds has been approximated as uniformly charged cylinders. The radius, thickness, and charge density of the charged region have been estimated to be about 1–20 km, 1–3 km, and 1–28 nC/m3, respectively. The lack of global magnetic fields on Venus has resulted in the formation of weak induced magnetic fields that give unrestricted access to Galactic Cosmic Rays (GCR). The ionization of the lower atmosphere of Venus due to GCR has been a subject of many earlier studies, and it has been considered a source for cloud electrification on Venus. The fields produced by charged regions with charge density levels from GCR-induced ionization do not exceed breakdown fields. The required levels of charge density could be produced by collisional charging.