Dual-Spacecraft Reconstruction of a Three-Dimensional Magnetic Flux Rope at Earth's Magnetopause

Monday, 15 December 2014
Hiroshi Hasegawa, ISAS Institute of Space and Astronautical Science, Department of Solar System Sciences, Kanagawa, Japan, Bengt Sonnerup, Dartmouth College, Hanover, NH, United States, Stefan Eriksson, Univ Colorado, Boulder, CO, United States, Takuma Nakamura, Los Alamos National Laboratory, Plasma Theory and App, Los Alamos, NM, United States and Hideaki Kawano, Kyushu University, Fukuoka, Japan
We present first results of a data analysis method, developed by Sonnerup and Hasegawa (2011), for reconstructing three-dimensional (3-D), magnetohydrostatic structures from data taken as two closely spaced satellites traverse the structures. The method is applied to a flux transfer event (FTE), which was encountered on 27 June 2007 by at least three (TH-C, TH-D, and TH-E) of the five THEMIS probes and was situated between two oppositely directed reconnection jets near the subsolar magnetopause under a southward interplanetary magnetic field condition. The recovered 3-D field indicates that a magnetic flux rope with a diameter of ~3000 km was embedded in the magnetopause. The FTE flux rope had a significantly 3-D structure, because the 3-D field reconstructed from the data from TH-C and TH-D (separated by ~390 km) better predicts magnetic field variations actually measured along the TH-E path than does the 2-D Grad-Shafranov reconstruction using the data from TH-C (which was closer to TH-E than TH-D and was at ~1000 km from TH-E). Such a 3-D nature suggests that reconnected field lines from the two reconnection sites are entangled in a complicated way through their interaction with each other. The generation process of the observed 3-D flux rope is discussed on the basis of the reconstruction results and the pitch-angle distribution of electrons observed in and around the FTE.


Sonnerup, B. U. Ö., and H. Hasegawa (2011), Reconstruction of steady, three-dimensional, magnetohydrostatic field and plasma structures in space: Theory and benchmarking, J. Geophys. Res., 116, A09230, doi:10.1029/2011JA016675.