Impact of E-Region Plasma Turbulence on Formation and Evolution of SAID/STEVE

Abstract

Subauroral Ion Drift (SAID) channels and Strong Thermal Emission Velocity Enhancement (STEVE) phenomena are distinct features of ionospheric dynamics that are accompanied by strong electric field forcing that is related to plasma turbulence in the E-region. This study investigates the role of the Farley-Buneman Instability (FBI) in modulating SAID and related phenomena, focusing on its impact on the evolution of extreme SAID channels. Using the Geospace Environment Model of Ion-Neutral Interactions (GEMINI), we incorporate macroscopic effects of FBI-induced turbulence in the form of anomalous electron heating and non-linear current density. Results demonstrate that FBI-induced turbulence produces a significant dampening effect on SAID channel velocity growth by increasing E-region conductance and density. This effect alters the electric field dynamics and moderates the extreme velocities characteristic of SAID channels. These findings underscore the critical role of including turbulence-driven processes in predictive models, advancing our understanding of magnetosphere-ionosphere coupling and space weather phenomena. This work is understood as missing physics that would increase the dampening effect, such as inelastic collisions and excitation of resonant cross-sections in electron neutral collisions, yet introduces itself as a starting point and an appeal to further improve.