Detection of High‐Latitude Magnetic Reconnection Between the Northward Interplanetary Magnetic Field and a Closed Magnetic Field Wedge Linked to a Transpolar Arc
Year: 2025
Type: article
Abstract: Transpolar arcs (TPAs) describe a subset of auroral emissions observed poleward of the Earth's main auroral ovals when the interplanetary magnetic field (IMF) is northward. These emissions are thought to align with a “wedge” of closed magnetic field lines extending to the high‐latitude boundary of the Earth's magnetosphere, where they are postulated to interact with the IMF through magnetic reconnection. Such an instance of “high‐latitude TPA wedge reconnection” is expected to open the Earth's magnetic field lines, but the event has never been verified by in situ observations. Here we report a detection of a high‐latitude TPA wedge reconnection site within one ion gyroradius distance on 18 March 2002, which manifests in the ionosphere as colocation of the TPA and a cusp spot. The result may explain previously reported cases of remotely detected “non‐lobe” high‐latitude magnetic reconnection, with implications for future understanding of TPAs and northward‐IMF global magnetospheric dynamics.
Source: Geophysical Research Letters
DOI: 10.1029/2025gl118830
Institutions: University of Southampton, University College London, Centre National de la Recherche Scientifique, Université Toulouse III - Paul Sabatier, Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Space Sciences Laboratory, University of California, Berkeley, Johns Hopkins University, Johns Hopkins University Applied Physics Laboratory
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,190
Funders: National Aeronautics and Space Administration, University of California Berkeley, Johns Hopkins University, Southwest Research Institute, European Space Agency, University of Leicester, University of Southampton, Natural Environment Research Council, Science and Technology Facilities Council
OpenAlex ID: W4417478473