Comparative Analysis of the Vlasiator Simulations and MMS Observations of Multiple X-Line Reconnection and Flux Transfer Events
| Autor: | Mojtaba Akhavan-Tafti, D. J. Gershman, Julia E. Stawarz, Minna Palmroth, Urs Ganse, Maxime Grandin, Guan Le, Jonathan Eastwood, James A. Slavin, Markus Battarbee |
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| Přispěvatelé: | Department of Physics, Space Physics Research Group, Particle Physics and Astrophysics |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
MECHANISM
Informatics 010504 meteorology & atmospheric sciences MOTION MAGNETOPAUSE 01 natural sciences global hybrid-Vlasov Vlasiator simulations MAGNETIC RECONNECTION Instruments and Techniques Interplanetary magnetic field Research Articles Physics Community Standards PLASMA reconnection-driven magnetic island dynamics Planetary Magnetospheres Magnetic flux Geophysics Magnetospheres Physics::Space Physics Magnetopause Planetary Sciences: Comets and Small Bodies Research Article flux transfer events 114 Physical sciences ELECTRON-DIFFUSION REGION Physics::Plasma Physics Electric field 0201 Astronomical and Space Sciences FTE evolution Results of the GEM Dayside Kinetics Southward IMF Challenge MESSENGER OBSERVATIONS Magnetospheric Physics FIELD Planetary Sciences: Solid Surface Planets Planetary Sciences: Fluid Planets 0105 earth and related environmental sciences Coalescence (physics) Solar Physics Astrophysics and Astronomy reconnection‐driven magnetic island dynamics Magnetic reconnection Plasma 115 Astronomy Space science Computational physics Magnetospheric Multiscale Mission Space and Planetary Science global hybrid‐Vlasov Vlasiator simulations Space Plasma Physics 0401 Atmospheric Sciences Interactions with Solar Wind Plasma and Fields |
| Zdroj: | Journal of Geophysical Research. Space Physics Journal of Geophysical Research: Space Physics |
| Popis: | The Vlasiator hybrid‐Vlasov code was developed to investigate global magnetospheric dynamics at ion‐kinetic scales. Here we focus on the role of magnetic reconnection in the formation and evolution of magnetic islands at the low‐latitude magnetopause, under southward interplanetary magnetic field conditions. The simulation results indicate that (1) the magnetic reconnection ion kinetics, including the Earthward pointing Larmor electric field on the magnetospheric side of an X‐point and anisotropic ion distributions, are well‐captured by Vlasiator, thus enabling the study of reconnection‐driven magnetic island evolution processes, (2) magnetic islands evolve due to continuous reconnection at adjacent X‐points, “coalescence” which refers to the merging of neighboring islands to create a larger island, “erosion” during which an island loses magnetic flux due to reconnection, and “division” which involves the splitting of an island into smaller islands, and (3) continuous reconnection at adjacent X‐points is the dominant source of magnetic flux and plasma to the outer layers of magnetic islands resulting in cross‐sectional growth rates up to + 0.3 RE 2/min. The simulation results are compared to the Magnetospheric Multiscale (MMS) measurements of a chain of ion‐scale flux transfer events (FTEs) sandwiched between two dominant X‐lines. The MMS measurements similarly reveal (1) anisotropic ion populations and (2) normalized reconnection rate ~0.18, in agreement with theory and the Vlasiator predictions. Based on the simulation results and the MMS measurements, it is estimated that the observed ion‐scale FTEs may grow Earth‐sized within ~10 min, which is comparable to the average transport time for FTEs formed in the subsolar region to the high‐latitude magnetopause. Future simulations shall revisit reconnection‐driven island evolution processes with improved spatial resolutions. Key Points Anisotropic ion distributions are reported in Vlasiator simulations and MMS observations of reconnection inflow regionsThe 2‐D simulations suggest magnetic islands grow mainly via continuous reconnection. Island coalescence, erosion, and division are also presentBased on simulation results, ion‐scale FTEs are estimated to grow at |
| Databáze: | OpenAIRE |
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