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Accueil > Séminaires et conférences > Séminaires, soutenances de thèses et HDR précédents > 2017 > Séminaires 2017 > Le vendredi 20 Octobre à 11 heures

Le vendredi 20 Octobre à 11 heures

Jérémy Dargent, IRAP et LPP
Titre/title : Numerical modeling of the cold ions dynamics during magnetic reconnection at the Earth’s magnetopause
Quand/When : 20 Octobre, 11 heures
Lieu/Where : Salle CPhT, aile 0

Résumé : Magnetic reconnection is a process allowing the conversion of magnetic energy into kinetic and thermal energies. It also leads to the mixing of plasmas. At the Earth’s magnetopause, in particular, it allows the transfer of energy and matter from the solar wind to the magnetosphere. The importance of this transfer depends on the reconnection rate, which is itself dependent on local plasma conditions. The recurrent presence of cold plasma populations of ionospheric origin at the magnetopause is proposed to impact the properties and efficiency of the process. This thesis looks into the effects of such cold populations on asymmetric magnetic reconnection using the state-of-the-art numerical kinetic simulations. The first part of this work focuses on the current sheet structure and demonstrates, using a recently developed kinetic equilibrium, that the initial equilibrium in fact does not impact the properties of the ensuing magnetic reconnection growth. The latter only depends on the instantaneously reconnecting plasma.
The second part of this thesis shows that when the plasma contains cold ions, these latter modify the expected observational signatures of reconnection sites. Magnetic reconnection heats and accelerates cold ions. The third part of this work predicts original signatures due to this dynamics and offers an analytical model to explain one of them. These results are being confronted with data from the recent MMS mission, which targets the study of reconnection sites at small scales.


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