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Accueil > Séminaires et conférences > Séminaires, soutenances de thèses et HDR précédents > 2011 > Séminaires 2011 > Le jeudi 10 novembre à 14h30

Le jeudi 10 novembre à 14h30

Anton ARTEMYEV (Space Research Institute, Russian Academy of Science, Moscow, Russia) :
’Thin current sheets in the Earth magnetotail : Cluster statistics, theoretical models and electrostatic effect’

Lieu : site de Saint-Maur

We use the statistics of 70 crossings by the Cluster mission to study and compare properties of thin current sheets observed at the dawn and dusk flanks of the Earth magnetotail. Special attention is devoted to the current sheet embedding : we define the degree of the current sheet embedding as be = Bext/B0 (B0 and Bext are magnetic field magnitudes at the thin current sheet boundary and in the lobes). We determine the current density by curlometer technique and calculate the current sheet thickness. We demonstrate that the current sheets at the dawn flank have larger be, smaller magnitude of the current density and larger relative thicknesses in Larmor radii than the current sheets at the dusk flank. Protons in thin current sheets are divided into two populations (the current‐carrying particles and the background) and the temperatures of these populations have been estimated. The proton current density (flow velocity in Y) is positive at the dusk flank and negative at the dawn flank, while the electron current density is positive at both flanks. This difference of the proton current density at two flanks is explained by the E x B drift due to the presence of the earthward electrostatic field Ex. We develop a simple model of the earthward electrostatic field to incorporate the influence of the embedding and the dawn‐dusk magnetic field component.


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Tutelles : CNRS Ecole Polytechnique Sorbonne Université Université Paris Sud Observatoire de Paris Convention : CEA
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Hébergeur : Laboratoire de Physique des Plasmas, Ecole Polytechnique route de Saclay F-91128 PALAISEAU CEDEX
Directeur de la publication : Pascal Chabert (Directeur)