HR: 0800h
AN: SH21C-0431    [Abstracts]
TI: Multispacecraft study of the topology of magnetic flux ropes at 1 AU
AU: * Hu, Q
EM: qiang.hu@ucr.edu
AF: University of California, Riverside, IGPP 1432 Geology Bldg, Riverside, CA 92521 United States
AU: Dasgupta, B
EM: Brahmananda.Dasgupta@ucr.edu
AF: University of California, Riverside, IGPP 1432 Geology Bldg, Riverside, CA 92521 United States
AB: Magnetic flux ropes are commonly observed by spacecraft in the solar wind at 1 AU. In this study, they are characterized by relatively large magnetic field magnitude, and smooth rotation of the magnetic field direction. They are not limited to well-defined magnetic clouds only. The Grad-Shafranov reconstruction technique has been applied to derive, quantitatively, the cross section of a magnetic flux rope directly from single spacecraft measurements. Previous studies have shown the non-axisymmetric cylindrical configuration of a single flux rope, and discovered multiple flux ropes embedded within otherwise a single structure, in an objective and self-consistent way. Applications of the technique to multiple spacecraft data sets are crucial to validate the technique and the results. Case studies are performed for several flux rope events when multi-point measurements from spacecraft ACE, Wind, and IMP8, etc, were available. The configuration of the flux rope structure as seen at each individual spacecraft will be visualized, and physical parameters associated with them will be reported and compared. In particular, we present a means to determine the magnetic helicity from our results. Possible evolution of the structure in the heliosphere will be discussed as well.
DE: 7819 Experimental and mathematical techniques
DE: 7843 Numerical simulation studies
DE: 2111 Ejecta, driver gases, and magnetic clouds
DE: 2134 Interplanetary magnetic fields
DE: 2164 Solar wind plasma
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2004 AGU Fall Meeting