Abstract
Abstract. The Birkeland currents, J||, electrically couple the high latitude ionosphere with the near Earth space environment. Approximating the spatial distribution of the Birkeland currents may be achieved using the divergence of the ionospheric electric field, , assuming zero conductance gradients such that . In this paper, electric field data derived from the Super Dual Auroral Radar Network (SuperDARN) are used to calculate , which is compared with the Birkeland current distribution derived globally from the constellation of Iridium satellites poleward of 60° magnetic latitude. We find that the assumption of zero conductance gradients is often a poor approximation. On the dayside, in regions where the SuperDARN electric field is constrained by radar returns, the agreement in the locations of regions of upward and downward current between and J|| obtained from Iridium data is reasonable with differences of less than 3° in the latitudinal location of major current features. It is also shown that away from noon, currents arising from conductance gradients can be larger than the component. By combining the estimate in regions of radar coverage with in-situ estimates of conductance gradients from DMSP satellite particle data, the agreement with the Iridium derived J|| is considerably improved. However, using an empirical model of ionospheric conductance did not account for the conductance gradient current terms. In regions where radar data are sparse or non-existent and therefore constrained by the statistical potential model the approximation does not agree with J|| calculated from Iridium data.
Highlights
Electromagnetic power of the order of tens of Giga Watts is continually deposited into the Earth’s ionosphere, heating the polar atmosphere, driving neutral winds, and creating a large system of circulating plasma (Richmond and Thayer, 2000)
Results of the fitting process were validated against full vector magnetometer data from Defence Meteorological Satellite Program (DMSP) or Oersted spacecraft
Because the Iridium magnetic field data are bundled in the satellite engineering packet, the time sampling of data sent to the ground is limited by the rate at which the large volume of engineering data can be transmitted
Summary
Electromagnetic power of the order of tens of Giga Watts is continually deposited into the Earth’s ionosphere, heating the polar atmosphere, driving neutral winds, and creating a large system of circulating plasma (Richmond and Thayer, 2000). This transfer of energy is largely driven by the interaction of the interplanetary medium with the magnetic field of the Earth causing field aligned currents to flow between the magnetosphere and ionosphere which close in the auroral ionosphere (Kelley, 1989). In the present paper we extend these studies using the maps of plasma convection provided as a SuperDARN data product to determine the extent
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
