Large-scale distributions of ionospheric horizontal and field-aligned currents inferred from EISCAT

• Main Authors: Fontaine, D., Peymirat, C.
• Other Authors: Centre d'étude des environnements terrestre et planétaires (CETP), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 1996
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; EISCAT
• Online Access: https://hal.archives-ouvertes.fr/hal-00329056; https://hal.archives-ouvertes.fr/hal-00329056/document; https://hal.archives-ouvertes.fr/hal-00329056/file/angeo-14-1284-1996.pdf

International audience Statistical models for large-scale convection and for ionospheric conductances were previously derived from observations of the incoherent-scatter radar EISCAT. We complete this large-scale description with statistical models of the horizontal and field-aligned currents achieved from the same data base and for the same ranges of the magnetic activity index Kp . Except for the high-latitude dayside currents generally located poleward of the radar field of view, a large part of the whole current system can be probed with EISCAT. Globally consistent with previously published models, our results also exhibit some differences, such as the asymmetry in the local-time extension of the current sheets, concentrated to a few hours around 18 MLT in the evening sector, while widely spread from premidnight to prenoon magnetic local times on the morningside. This statistical description of the current system above EISCAT allowed us to examine several aspects of the large-scale auroral electrodynamics, namely the relationships between convection, conductances, and currents, in particular in the vicinity of the Harang discontinuity, and the features of the global current circuit.