FG: 3D Ionospheric Electrodynamics and Its Impact on the Magnetosphere-Ionosphere-Thermosphere Coupled System

Focus Group Chairs

• Hyunju Connor (hyunju.k.connor@nasa.gov), NASA GSFC
• Bin Zhang (binzheng.zhang@dartmouth.edu), HAO
• Gang Lu (ganglu@ucar.edu) Expertise: IT coupling, TIEGCM – AMIE
• Haje Korth (haje.korth@jhuapl.edu) Expertise: MI coupling, AMPERE observations

Term: Five years (2017-2021)

Topic

The magnetosphere is one of the major energy sources that drive the Earth's upper atmosphere. During geomagnetic storms, the magnetosphere transmits significant energy and momentum into the upper atmosphere via field-aligned currents, Poynting flux, and auroral precipitation. In response, the ionospheric electric potentials and conductances increase, the thermosphere heats and expands, and the global atmospheric circulation changes. The ionosphere – thermosphere feedback can also influence magnetospheric dynamics. The heated thermosphere can enhance ionospheric outflows and change magnetic reconnection rates. The modified global circulation redistributes plasmas and neutrals, alters the ionospheric conductance and electric field, and thus changes the magnetospheric convection and reconnection. Although strong coupling of the magnetosphere – ionosphere – thermosphere (MIT) system are widely recognized by the space science community, studying this coupling dynamics as a whole global system has yet to be conducted comprehensively. To magnetospheric scientists, the ionosphere is treated as a two- dimensional, low-altitude boundary. The mass and momentum exchanges between the magnetosphere and the IT system are often ignored. More realistic calculation of upper atmospheric dynamics is necessary in the global magnetosphere - ionosphere models. To upper atmospheric scientists, simple statistical convection patterns and empirical auroral precipitation fluxes driven by the Kp and hemispheric power indices are commonly used to infer complicated magnetospheric dynamics. As a consequence, global IT models (e.g. CTIPe, TIEGCM, and GTIM) cannot sufficiently capture the spatiotemporal dynamics of magnetospheric energy sources during strong geomagnetic activities, thus limiting the predictive capability of these models when it is most needed. More realistic calculation of magnetospheric energy input is necessary. In recent years, the coupled magnetosphere – ionosphere – thermosphere (MIT) models (e.g. OpenGGCM- CTIM, LFM-TIEGCM, BATSRUS-GTIM, and AMIE-TIEGCM) have been gradually matured to the point to revisit the extensive ground/space observations and to investigate the complex coupling processes of the MIT system. It is thus the proper time to build on and expand these recent efforts. For the next five years, this new focus group (FG) will address, via modeling and observational approaches, 1) where, when, and how magnetospheric energy contributes to the IT system and 2) how the IT system feeds back to the magnetosphere.