Journal cover Journal topic
Annales Geophysicae Sun, Earth, planets, and planetary systems An interactive open-access journal of the European Geosciences Union
Ann. Geophys., 36, 53-57, 2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 3.0 License.
ANGEO Communicates
18 Jan 2018
On the role of neutral flow in field-aligned currents
Anthony J. Mannucci1, Olga P. Verkhoglyadova1, Xing Meng1, and Ryan McGranaghan1,2 1Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
2University Corporation for Atmospheric Research (UCAR), CPAESS, Boulder, CO 80301, USA
Abstract. In this brief note we explore the role of the neutral atmosphere in magnetosphere–ionosphere coupling. We analyze momentum balance in the ion rest frame to form hypotheses regarding the role of neutral momentum in the lower ionosphere during geomagnetic storms. Neutral momentum that appears in the ion rest frame is likely the result of momentum imparted to ionospheric ions by solar wind flow and the resultant magnetospheric dynamics. The resulting ion-neutral collisions lead to the existence of an electric field. Horizontal electron flow balances the momentum supplied by this electric field. We suggest a possible role played by the neutral atmosphere in generating field-aligned currents due to local auroral heating. Our physical interpretation suggests that thermospheric neutral dynamics plays a complementary role to the high-latitude field-aligned currents and electric fields resulting from magnetospheric dynamics.

Citation: Mannucci, A. J., Verkhoglyadova, O. P., Meng, X., and McGranaghan, R.: On the role of neutral flow in field-aligned currents, Ann. Geophys., 36, 53-57,, 2018.
Publications Copernicus
Short summary
We performed a theoretical study of how the Earth’s ionosphere interacts with the tenuous magnetosphere above it. We asked the following: what leads to electric fields and electric currents flowing between these two regions? We concluded that one source of currents flowing between these regions is the localized heating of neutral gas by energetic particles precipitating from above (the magnetosphere).
We performed a theoretical study of how the Earth’s ionosphere interacts with the tenuous...