First Results from Including Macroscopic Effects of Small-Scale E-Region Turbulence in Global Magnetosphere-Ionosphere-Thermosphere (MIT) Models

Abstract:

During times of strong magnetospheric disturbances, large-amplitude electric fields penetrate from the Earth’s magnetosphere to the E-region ionosphere where they generate small-scale plasma density turbulence. This turbulence induces nonlinear currents and leads to anomalous electron heating. Current global MIT models completely disregard these nonlinear effects by assuming simple laminar ionospheric flows. This talk will present the results from incorporating these effects separately into both the TIEGCM ionosphere and the LFM magnetosphere simulators. Adding models of anomalous E-region heating to TIEGCM leads to significant changes in ionospheric electron density, temperature, and conductivity in the E region, often exceeding the effects of particle precipitation. Adding anomalous E-region conductivies to LFM causes a range of effects to the structure of the magnetosphere plus it reduces the cross-polar-cap potential by about 25%. In both simulators it allows the field-aligned currents to close in a smaller volume and at higher amplitudes, modifying the nature of energy deposition. This work shows that, in order to accurately model Space Weather, researchers require physically accurate E-region conductivities.