Modeling of auroral scintillation produced by energetic electron precipitation using ionospheric plasma and forward propagation models

The electron density structures (irregularities) in the ionosphere modify the phase and amplitude of transionospheric radio signals; such fluctuations are termed “scintillations”. In the cusp and polar cap regions, scintillation is often associated with irregularities from F-region plasma instabilities arising from density inhomogeneities and shearing. In the auroral zone, however, a strong correlation has been observed between the scintillation and the auroral arcs produced by electron precipitation forming E- and F-region density structures. In this work, we investigate the effects of electron precipitation on the formation of scintillation-producing density irregularities using a high-resolution (~250 m), physics-based, plasma structuring model, the “Geospace Environment Model of Ion-Neutral Interactions” (GEMINI), coupled to a radio propagation model, the “Satellite-beacon Ionospheric-scintillation Global Model of the upper Atmosphere” (SIGMA). We test various types of structure precipitation intended to model auroral arcs to induce the scintillation-producing density irregularities. We highlight the effects of electron precipitation by varying their total energy flux and characteristic energies. We examine the sensitivity of structures and their different precipitation seeding to different satellite frequencies (e.g., VHF, UHF, L-band) and satellite ray paths. The data from collocated scintillation arrays, all-sky camera, and incoherent scatter radar at the Poker Flat Research Range near Fairbanks, AK, can be used for more realistic constraints on precipitation, multiscale flow, and density structures hence plasma dynamics for auroral events. Case studies to model a specific event might lead to a better quantitative understanding of the observability of auroral scintillation-related plasma processes.