Development of SpriteOptics: A Python-Based Framework for Synthetic Optical Emission Modeling of Sprite Streamers

Abstract

Transient Luminous Events (TLEs), particularly sprites, are short-lived electrical discharges occurring in the upper atmosphere and producing characteristic optical emissions. Numerical streamer simulations provide valuable information on their dynamics and electrodynamic properties; however, linking simulated plasma variables to potentially observable optical signals requires additional post-processing. This work presents SpriteOptics v1.0, a Python-based computational tool developed to estimate synthetic optical emissions from plasma simulation outputs. The software processes VTK files containing electric-field and electron-density data, calculates the reduced electric field E/N, and incorporates excitation coefficients obtained with BOLSIG+ using LXCat data. The model accounts for excited-state populations through a quasi-steady-state (QSS) approximation, collisional quenching, radiative emission, and atmospheric attenuation. It also incorporates volumetric reconstruction of axisymmetric simulations, geometric dilution, and a configurable field of view. SpriteOptics estimates the temporal evolution of emissions associated with 337 nm (N₂ 2PN₂), LBH (N₂), and 777.4 nm (O I), generating synthetic irradiance time series and data files for subsequent analysis. The software provides a modular framework for linking plasma simulations with optical observables and enables the future incorporation of more comprehensive atmospheric, chemical, radiative-transfer, and instrumental models.