Multiple-spacecraft study of an extended magnetic structure in the solar wind

Abstract

An extended magnetic structure was observed consecutively by five spacecraft (ACE, WIND, STEREO A and B, and CLUSTER) in the solar wind on 15 January 2007. The similar bipolar magnetic field variations from five spacecraft suggest that the magnetic structure is two-dimensional. The abrupt disappearance of the beam electrons in the core of the structure suggests that the core of the structure is magnetically isolated from the surrounding environment. Our analysis shows that this magnetic structure is a magnetic flux rope, which extends over at least 180 RE in space. The length and orientation of the flux rope were determined by a local minimum variance analysis (MVA) from individual spacecraft observations of the magnetic field and a timing analysis based on the joint observations by all five spacecraft. The results show that the orientation of the flux rope stays constant in space and time. The flux rope is embedded in a corotating interaction region (CIR), which followed a magnetic cloud. © 2009 by the American Geophysical Union.