Premium
Observation of Three‐Dimensional Magnetic Reconnection in the Terrestrial Magnetotail
Author(s) -
Zhou Meng,
AshourAbdalla Maha,
Deng Xiaohua,
Pang Ye,
Fu Huishan,
Walker Raymond,
Lapenta Giovanni,
Huang Shiyong,
Xu Xiaojun,
Tang Rongxin
Publication year - 2017
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2017ja024597
Subject(s) - magnetic reconnection , physics , magnetic field , line (geometry) , field line , ion , plane (geometry) , magnetohydrodynamics , magnetic flux , flux (metallurgy) , electron , spacecraft , computational physics , geometry , astronomy , mathematics , materials science , quantum mechanics , metallurgy
Study of magnetic reconnection has been focused on two‐dimensional geometry in the past decades, whereas three‐dimensional structures and dynamics of reconnection X line are poorly understood. In this paper, we report Cluster multispacecraft observations of a three‐dimensional magnetic reconnection X line with a weak guide field (~25% of the upstream magnetic field) in the Earth's magnetotail. We find that the X line not only retreated tailward but also expanded across the tail following the electron flow direction with a maximum average speed of (0.04–0.15) V A,up , where V A,up is the upstream Alfvén speed, or (0.14–0.57) V de , where V de is the electron flow speed in the out‐of‐plane direction. An ion diffusion region was observed by two spacecraft that were separated about 10 ion inertial lengths along the out‐of‐plane direction; however, these two spacecraft observed distinct magnetic structures associated with reconnection: one spacecraft observed dipolarization fronts, while the other one observed flux ropes. This indicates that reconnection proceeds in drastically different ways in different segments along the X line only a few ion inertial lengths apart.