Magnetic reconnection exhausts in the solar wind are often associated with interplanetary coronal mass ejections (ICMEs). Occasionally, an exhaust is observed at the interface between ambient solar wind and the leading edge of an ICME where reconnection serves to erode away some of the magnetic flux carried by the ICME. More often the exhausts are observed at thin current sheets within the interiors of ICMEs or near their trailing edges. We have examined an unusually large set of seven reconnection exhausts, including both sunward and antisunward directed events, observed within the interior of and near the trailing edge of an ICME. Six of these exhausts occurred as pairs on the opposite sides of relatively small magnetic filaments of locally reversed fields. For three of the exhausts the local magnetic shear was considerably less than 90°, indicating that reconnection can occur at times when the so-called guide field component considerably exceeds the antiparallel field component. One exhaust had a local width of only 1.6 × 103 km (25.4 ion inertial lengths) and was convected past the Wind spacecraft in ∼5.4 s. No Hall field rotations were observed in association with this event, probably because of the significant guide field present and because even this extremely narrow exhaust was probably sampled well downstream (∼380 ion inertial lengths) from the reconnection site. The current sheets bounding the exhaust had widths of 3.5 and 5.2 ion inertial lengths, respectively, exceeding by several times the expected scale size of the associated diffusion region.
All Science Journal Classification (ASJC) codes
- Space and Planetary Science