SM059-03
Temporal evolution of flux tube entanglement at the magnetopause

Wednesday, 16 December 2020: 16:06
Virtual
Yi Qi, University of California, Los Angeles, Department of Earth, Planetary, and Space Sciences, Los Angeles, CA, United States, Christopher T Russell, University of California, Los Angeles, CA, United States, Ying-Dong Jia, UCLA-IGPP, Los Angeles, CA, United States, Robert J Strangeway, UCLA IGPP/ESS, Los Angeles, CA, United States, Mark Alexander Alexander Hubbert, University of California Los Angeles, Los Angeles, CA, United States, James L Burch, Southwest Research Institute San Antonio, San Antonio, TX, United States, Roy B Torbert, Univ New Hampshire, Durham, NH, United States, William R Paterson, NASA Goddard Space Flight Center, Geospace Physics Laboratory, Greenbelt, MD, United States and Barbara L Giles, NASA Goddard Space Flight Center, Greenbelt, MD, United States
Abstract:
Flux transfer events (FTEs), bundles of twisted field lines, in the form of flux ropes (FRs), are believed to be the product of magnetic reconnection at the magnetopause and a key agent for the solar wind energy transfer into the terrestrial magnetosphere. However, the journey of the flux tubes may not always be straightforward. Recent observations show that two reconnected flux tubes between two reconnection lines, moving in opposite directions along the magnetopause may collide and become entangled. Then magnetic flux piles up at the interface, producing secondary reconnection at that site. As a result, a new pair of flux ropes with different connectivity in contrast to the initial pair may be produced. One rope has its two ends in the magnetosphere while the other has its two ends connected to the magnetosheath. In order to determine how the entanglement develops in time, we examine multiple entanglement events observed by the Magnetospheric Multiscale (MMS). The By dominated interplanetary magnetic field (IMF) distribution agrees with previous findings. Through comparison with their magnetic field geometry and pressure enhancement, we identify three representative evolutionary stages. Our study confirms the flux rope nature of flux transfer events and explains how, a disparate pair of ropes is formed from two ropes each connected to a different hemisphere of the magnetosphere.
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