HR: 16:45h
AN: SH34A-04    [Abstracts]
TI: The Sheared Sub-Parker Spiral
AU: * Schwadron, N A
EM: nschwadron@swri.edu
AF: Southwest Research Institute, 6220 Culebra, San Antonio, TX 78238-5166 United States
AU: McComas, D J
EM: dmccomas@swri.edu
AF: Southwest Research Institute, 6220 Culebra, San Antonio, TX 78238-5166 United States
AB: Recent studies have shown that, in selected cases, the heliospheric magnetic field is much more radial than the standard Parker spiral in the rarefactions of co-rotation interaction regions (CIRs). This reveals that open field footpoints at the Sun move through the coronal hole boundary, which causes magnetic field lines to be connected and stretched across the fast-slow wind transition. Here we include footpoint motion at the Sun in a magneto-hydrodynamic (MHD) model to describe the formation and evolution of a CIR out to 5 AU. We compare results with Ulysses observations in CIR rarefactions. In comprehensive observations of CIRs observed by Ulysses from 1992 through 1997, we find that the more radial field, the "sheared sub-Parker spiral", is almost always present in CIR rarefactions. These observations show striking evidence for both systematic footpoint motions strongly consistent with differential rotation, and random footpoint motions, consistent with interchange reconnection that continually reconfigures the open magnetic field. Thus, we reveal the sheared sub-Parker spiral of the inner heliospheric magnetic field, and discuss its broad implications for the origin of solar wind, the nature of coronal holes, and the magnetic structure of the heliosphere.
DE: 2102 Corotating streams
DE: 2109 Discontinuities
DE: 2134 Interplanetary magnetic fields
DE: 2164 Solar wind plasma
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2004 AGU Fall Meeting