Mid-Latitude and Equatorial Dynamics of the Ionosphere - Thermosphere System

       The overarching goal of this Focused Science Topic (FST) team is to advance our understanding of the mid-latitude and equatorial ionospheric-thermospheric dynamics, the generation of ionospheric irregularities, the longitudinal variability of the ionosphere-thermosphere system, and the driving mechanisms for the longitudinal variability. During geomagnetic storms, the interplanetary electric field penetrates to low latitudes, producing penetration electric fields. Storm-time Joule and particle heating in the auroral zones launches disturbance winds that propagate to low latitudes, producing disturbance dynamo electric fields. The region-2 field-aligned currents generate shielding electric fields at lower latitudes that are largely in the same direction as disturbance dynamo electric fields and can partly reduce penetration electric fields. Large-scale traveling ionospheric/atmospheric disturbances are also generated by the enhanced Joule and particle heating and propagate to low latitudes. In addition, atmospheric gravity waves and tides excited at lower altitudes can propagate to ionospheric altitudes. All these forcing processes from the solar wind and magnetosphere, as well as from below, affect ionospheric dynamics at middle and low latitudes.

The research objectives of this FST team are to address the following outstanding science issues:

1. What are the characteristics of penetration and disturbance dynamo electric fields during magnetic storms?

2. What are the longitudinal variations of ionospheric parameters and the drivers for the longitudinal variations?

3. What are the driving processes for the generation of plasma instabilities, plasma bubbles and structures at middle and low latitudes?

4. What controls the generation and propagation of storm-time large-scale traveling ionospheric and atmospheric disturbances?

      We will analyze extensive data sets from multiple satellites and ground-based measurements and run first-principles and data-assimilative models to address the above science issues.

      Models that will be used by this team include: Global Ionosphere Thermosphere Model (GITM), Multiscale Atmosphere-Geospace Environment (MAGE) model, Multimodel Ensemble Prediction System (MEPS), SAMI3, Space Weather Modeling Framework (SWMF), Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM), The Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension (WACCM-X), etc.

      Data sets include plasma drift velocities, plasma density and temperature, ion composition, neutral composition and emission, and neutral winds measured by the C/NOFS, DMSP, GOCE, CHAMP, GOLD, TIMED, GRACE, and Swarm satellites; GNSS/TEC; ionospheric ion density and drift velocities measured by ionospheric radars; magnetic fields measured by the AMPERE network; etc.