ALBERT

Description: How the solar wind affects the location of the magnetopause has been widely studied and excellent models of the magnetopause based on in situ observations in the solar wind and at the magnetopause have been established, while the careful insight into the responses of the magnetopause to the variations in the solar wind can still provide us some new information about the processes in space plasmas. The short distance from Cluster to TC-1 on 9 March 2004, between 06:10 and 08:10 UT, gives us a good opportunity to precisely monitor the responses of the magnetopause to the variations in the solar wind. On the basis of the combined observations between Cluster, TC-1, and SuperDARN we analyze the magnetopause crossings associated with magnetopause motion or magnetic reconnection when the solar wind conditions have a series of variations. New results about the time delays for the propagation from the solar wind monitor to the magnetopause of the interplanetary magnetic fields (IMF) and of the solar wind dynamic pressure, respectively, and the intrinsic time for reconnection onset at the magnetopause are obtained. The most important feature of the event is that the dynamic pressure and the IMF in the solar wind do not arrive at the magnetopause at the same time, which will direct us to find out how the variation in the solar wind dynamic pressure is transported from the bow shock to the magnetopause. Another significant feature is that this event presents a shorter intrinsic time, ∼2 min, for reconnection onset at the dayside magnetopause than that given by the previous work of Le et al. (1993) and Russell et al. (1997).

Description: [1]  The fine magnetic field structure of two successive plasmoids previously reported are investigated by magnetic rotation analysis (MRA) using four Cluster satellite data. Between these two plasmoids, opposite trends of curvature radius ( R c ) variations of the magnetic field lines from the boundary to the inner part are found. The different variations of R c reflect that the two plasmoids have different magnetic configurations. The electric current density distributions for both plasmoids are found distinct. The By increase and abundant field-aligned currents in the narrow core region of first plasmoid indicate that a possible magnetic flux rope (MFR) core exists inside. The results allow to identify that the first observed plasmoid is of magnetic loop (ML) type (with possible MFR core) and the second plasmoid is of magnetic flux rope (MFR) type. The coexistence of ML and MFR in the near-Earth plasma sheet may imply that multiple X-line reconnection (MXR) can occur by either anti-parallel or component-parallel way.