A magnetic cloud with unusual structure and corresponding bow shock movement observed on May 13, 1995

T. Takeuchi, T. Araki, R. P. Lepping, T. Yamamoto, S. Kokubun, T. Nagai, and T. Iyemori

Department of Geophysics, Kyoto University, Japan


A magnetic cloud embedded in a corotating interaction region was observed by Wind 244 RE upstream of Earth on May 13, 1995. This cloud was unusual as it had at least two internal structures and the profile of the magnetic field strength was far from that predicted by a simple force-free flux rope model, although the field direction fit well. About 90 min later, this cloud was detected by the IMP 8 and Geotail satellites in front of Earth's bow shock 8 min after the passage of the front boundary. An earthward movement of the bow shock was observed about 3 hours later. From the normal vector of the bow shock front, we deduce that the shape of the expanding bow shock was distorted from an axially symmetric geometry. The shape was consistent with distortion due to the observed inclination of the front boundary of the magnetic cloud.

Geophys. Res. Lett., Vol. 25, No. 17, 3269-3272, 1998