Lightning-Ionosphere Interactions: An Accurate, Simplified Nighttime Mesospheric Photochemistry Model

Lightning-ionosphere interactions are well documented in the form of observations of fantastic optical emissions such as sprites and elves.  In order to better understand electromagnetic heating of the lower ionosphere (∼60-100 km altitude), a mesospheric photo-chemistry model is employed to interpret lightning-ionosphere interactions. The LIMA atmospheric chemistry model implements >150 chemical reactions, as do similar atmospheric chemistry models, such as WACCM, but the LIMA model has had success modeling so-called Long Recovery Events. Due to the large number of reactions and chemical species involved, however, it can be difficult to identify specific cause and effect mechanisms for the event of interest. This paper presents a simplified mesospheric chemistry model that accurately reproduces lightning-ionosphere interactions predicted by the full 167-reaction LIMA model (it maintains the accuracy of the full LIMA model for electron density, electron temperature, electrical conductivity, and electromagnetic field intensity as a function of time and space throughout the heating process).