Cusp dynamics under northward IMF using three-dimensional global particle-in-cell simulations
Résumé
The interaction of the solar wind with the terrestrial magnetosphere is analyzed with the help of three-dimensional (3-D) global, full-electromagnetic particle-in-cell (PIC) simulations, in the configuration where the interplanetary magnetic field (IMF) is steadily northward. The present study is mainly focused on the cusp region and associated particle momenta dynamics. Within the present context and to the best of our knowledge, this work represents the first numerical simulation for analyzing the cusp dynamics using a fully self-consistent 3-D kinetic and electromagnetic approach. The main goals of the study are the following: (i) to retrieve the main known features of the cusp to validate the use of 3-D PIC “global” simulations, (ii) to compare with previous results obtained with 3-D MHD simulations, (iii) to create an updated global view of the cusp based on use of 3-D PIC simulation, which cannot be obtained from a MHD approach, and (iv) to compare with statistical results from the Cluster mission. In particular, the stagnant exterior cusp (SEC) identified in previous statistical analysis of experimental data is retrieved, and it is possible to more precisely define the edges of the SEC region. In addition, we will focus on cusp features recently observed by the Cluster mission, for example, the Alfvén Transition Layer or ATL and on the features not reproduced by either MHD or the hybrid approach, which have been used to characterize the outer edges of the cusp more clearly.
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