| Autor: |
Laundal, K. M., Yee, J. H., Merkin, V. G., Gjerloev, J. W., Vanhamäki, H., Reistad, J. P., Madelaire, M., Sorathia, K., Espy, P. J. |
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| Zdroj: |
Journal of Geophysical Research. Space Physics; May2021, Vol. 126 Issue 5, p1-16, 16p |
| Abstrakt: |
The auroral electrojet is traditionally measured remotely with magnetometers on ground or in low Earth orbit (LEO). The sparse distribution of measurements, combined with a vertical distance of some 100 km to ground and typically >300 km to LEO satellites, means that smaller scale sizes can't be detected. Because of this, our understanding of the spatiotemporal characteristics of the electrojet is incomplete. Recent advances in measurement technology give hope of overcoming these limitations by multi‐point remote detections of the magnetic field in the mesosphere, very close to the electrojet. We present a prediction of the magnitude of these disturbances, inferred from the spatiotemporal characteristics of magnetic field‐aligned currents. We also discuss how Zeeman magnetic field sensors (Yee et al., 2021) onboard the Electrojet Zeeman Imaging Explorer satellites will be used to essentially image the equivalent current at unprecedented spatial resolution. The electrojet imaging is demonstrated by combining carefully simulated measurements with a spherical elementary current representation using a novel inversion scheme. Plain Language Summary: The interaction between the solar wind and the Earth's magnetic field produces electric currents in the ionosphere which are closely associated with auroral activity. The magnetic effects of these currents have so far been measured remotely, with ground magnetometers which are about 100 km below the currents, or with satellite magnetometers that are even further away, but above the currents. Since, the currents have only been measured from a distance, we only know their large‐scale structure. This limitation can be overcome by using new sensor technology that can be carried on small satellites in low Earth orbit. Such an instrument will measure oxygen emissions from the upper atmosphere, just below the currents. These emissions change in the presence of a magnetic field due to quantum effects, and can therefore be used to infer magnetic disturbances. We demonstrate a technique to create high‐resolution two‐dimensional maps of the magnetic field disturbances, using simulated data from an upcoming satellite mission. Key Points: We describe a technique to image the electrojet from low Earth orbit using the Zeeman effectSimulation results show that the technique can resolve meso‐scale structures in the electrojetA novel inversion scheme for spherical elementary current representation is presented [ABSTRACT FROM AUTHOR] |
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Complementary Index |
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