Fractal Modeling of Lightning and TLEs through the Solar System

Possible evidence of extraterrestrial electrical activity has been formally investigated since the early 1980s (see, Rakov & Uman, 2001, Chapter 16). This inquiry became substantive following the detection of tweeks, sferics, and whistlers on the gas and ice giants as part of the Voyager missions (Gurnett et al., 1979 for Jupiter; Warwick et al., 1981 for Saturn; Zarka & Pedersen, 1986 for Uranus; Gurnett et al., 1990 for Neptune). The discovery of transient luminous events (TLEs) further revealed the diversity of atmospheric electrical activity. Concrete evidence of sprites (Sentman et al., 1995), blue jets (Wescott et al., 1995), and gigantic jets (Pasko et al., 2002) here on Earth broadened the scope of our exploration for extraterrestrial atmospheric electricity. Yair et al. (2008) suggested the possibility of extraterrestrial sprites, and indications of TLEs measured by Jupiter’s Juno (Giles et al., 2020) appear to confirm these suspicions. Here we propose a unified model to simulate atmospheric electricity across the solar system. This one-way coupling bridges atmospheric and lightning models. NASA Global Reference Atmospheric Models (GRAMs) and the Jupiter-focused Explicit Planetary Isentropic-Coordinate model (EPIC) let us determine the thermodynamic properties and meteorological conditions required for convection-induced charge separation and subsequent dielectric breakdown. All simulation parameters are supplemented and justified through the existing peer-reviewed literature. These thresholds and charge distributions become input parameters for the FRActal Model of Electrostatic Discharges (FraMED). To ensure the overall neutrality of the discharge, the potential is updated after every step. Once the simulation has determined a termination point, the discharge is classified based upon its charge transfer, propagation distance, and dipole moment, and compared to known observations values to confirm validity. This approach is applied to the atmospheres of Venus, Earth, Mars, Jupiter, Titan, Uranus, and Neptune for both leaders and streamers. In addition, the simulations of shallow lightning and TLEs in and Jupiter’s water cloud layer are compared to Juno data and prepared for publication. In cases where discharges have not been observed or meteorological conditions are not suitable for discharges, the results nonetheless provide valuable insight on the minimum conditions under which discharges would occur.