Coordinated Cluster, ground-based instrumentation and low-altitude satellite observations of transient poleward-moving events in the ionosphere and in the tail lobe

• Main Authors: Lockwood, M., Opgenoorth, H., van Eyken, A. P., Fazakerley, A., Bosqued, J.-M., Denig, W., Wild, J. A., Cully, C., Greenwald, R., Lu, G., Amm, O., Frey, H., Strømme, A., Prikryl, P., Hapgood, M. A., Wild, M. N., Stamper, R., Taylor, M., Mccrea, I., Kauristie, K., Pulkkinen, T., Pitout, F., Balogh, A., Dunlop, M., Rème, H., Behlke, R., Hansen, T., Provan, G., Eglitis, P., Morley, S. K., Alcaydé, D., Blelly, P.-L., Moen, J., Donovan, E., Engebretson, M., Lester, M., Watermann, J., Marcucci, M. F.
• Other Authors: Solar Terrestrial Physics Division Didcot, Space Science and Technology Department Didcot (RAL Space), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC)-Science and Technology Facilities Council (STFC)-STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC)-Science and Technology Facilities Council (STFC), School of Physics and Astronomy Southampton, University of Southampton, IRF, EISCAT Scientific Association, Mullard Space Science Laboratory (MSSL), University College of London London (UCL), Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), AFRL Space Vehicles Directorate, Air Force Research Laboratory (AFRL), United States Air Force (USAF)-United States Air Force (USAF), Department of Physics and Astronomy Leicester, University of Leicester, University of Calgary, Remote Sensing Group, Johns Hopkins University Applied Physics Laboratory Laurel, MD (APL), High Altitude Observatory (HAO), National Center for Atmospheric Research Boulder (NCAR), Finnish Meteorological Institute (FMI), University of California, University of California (UC), University of Tromsø (UiT), Communications Research Centre Canada (CRC), Blackett Laboratory, Imperial College London, Department of Physics Oslo, Faculty of Mathematics and Natural Sciences Oslo, University of Oslo (UiO)-University of Oslo (UiO), Department of Physics Minneapolis, Augsburg College, Danish Meteorological Institute (DMI), Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2001
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Longyearbyen; Svalbard; EISCAT
• Online Access: https://hal.science/hal-00329215; https://hal.science/hal-00329215/document; https://hal.science/hal-00329215/file/angeo-19-1589-2001.pdf

International audience During the interval between 8:00–9:30 on 14 January 2001, the four Cluster spacecraft were moving from the central magnetospheric lobe, through the dusk sector mantle, on their way towards intersecting the magnetopause near 15:00 MLT and 15:00 UT. Throughout this interval, the EISCAT Svalbard Radar (ESR) at Longyearbyen observed a series of poleward-moving transient events of enhanced F-region plasma concentration ("polar cap patches"), with a repetition period of the order of 10 min. Allowing for the estimated solar wind propagation delay of 75 ( ± 5) min, the interplanetary magnetic field (IMF) had a southward component during most of the interval. The magnetic footprint of the Cluster spacecraft, mapped to the ionosphere using the Tsyganenko T96 model (with input conditions prevailing during this event), was to the east of the ESR beams. Around 09:05 UT, the DMSP-F12 satellite flew over the ESR and showed a sawtooth cusp ion dispersion signature that also extended into the electrons on the equatorward edge of the cusp, revealing a pulsed magnetopause reconnection. The consequent enhanced ionospheric flow events were imaged by the SuperDARN HF backscatter radars. The average convection patterns (derived using the AMIE technique on data from the magnetometers, the EISCAT and SuperDARN radars, and the DMSP satellites) show that the associated poleward-moving events also convected over the predicted footprint of the Cluster spacecraft. Cluster observed enhancements in the fluxes of both electrons and ions. These events were found to be essentially identical at all four spacecraft, indicating that they had a much larger spatial scale than the satellite separation of the order of 600 km. Some of the events show a correspondence between the lowest energy magnetosheath electrons detected by the PEACE instrument on Cluster (10–20 eV) and the topside ionospheric enhancements seen by the ESR (at 400–700 km). We suggest that a potential barrier at the magnetopause, which prevents the lowest ...