Magnetosphere‐ionosphere‐thermosphere coupling: Effect of neutral winds on energy transfer and field‐aligned current

Abstract

The assimilative mapping of ionospheric electrodynamics (AMIE) algorithm has been applied to derive the realistic time‐dependent large‐scale global distributions of the ionospheric convection and particle precipitation during a recent Geospace Environment Modeling (GEM) campaign period: March 28‐29, 1992. The AMIE outputs are then used as the inputs of the National Center for Atmospheric Research thermosphere‐ionosphere general circulation model to estimate the electrodynamic quantities in the ionosphere and thermosphere. It is found that the magnetospheric electromagnetic energy dissipated in the high‐latitude ionosphere is mainly converted into Joule heating, with only a small fraction (6%) going to acceleration of thermospheric neutral winds. Our study also reveals that the thermospheric winds can have significant influence on the ionospheric electrodynamics. On the average for these 2 days, the neutral winds have approximately a 28% negative effect on Joule heating and approximately a 27% negative effect on field‐aligned currents. The field‐aligned currents driven by the neutral wind flow in the opposite direction to those driven by the plasma convection. On the average, the global electromagnetic energy input is about 4 times larger than the particle energy input.