Unified Model of Lightning & Electrostatic Discharges Across the Solar System

Abstract

As we increase the number of probes on other objects within our solar system, it becomes all the timelier to understand the physics of electrostatic discharges (ESDs). Since these probes will have sensitive instruments on-board, we will need to apply our existing knowledge of ESDs to extraterrestrial environments to protect these investments from deterioration. On Earth, even small-scale ESDs can permanently destroy critical components within electronics, while large-scale ESDs (e.g., lightning strikes) are capable of debilitating entire power grids. The characteristic timescale of an ESD is small compared to the timescales of cloud charging and storm evolution. This lets us approximate the background electric field as static for the duration of the discharge. The development of atmospheric discharges involves high electric fields that originate from atmospheric clouds constructed from charge layers, whose dimensions, placements, and charge densities define the electric fields everywhere within a mesoscale size domain. The FraMED model has been proven successful in simulating diverse atmospheric processes on Earth including lightning and Transient Luminous Events (TLEs). Here we develop a unified model for lightning discharges on solar system objects to explore how it can characterize extraterrestrial atmospheric electricity. This requires adaptability to new atmospheric composition and ultimately its extension to streamer-based in addition to leader-based discharges. Whenever possible, the results are compared with documented events to confirm the model’s accuracy. Simulations on bodies where lightning has not yet been observed cannot be similarly validated, but still provide critical information on the conditions likely to produce energetic discharges. By predicting the likelihood and intensity of ESDs in these extraterrestrial environments, these insights will help design requirements for future satellites and probes and potentially prevent significant financial loss.