On The Solar Origins of Open Magnetic Fields in the Heliosphere |
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Dave Rust Submitted: 2008-10-13 12:06
A combination of heliospheric and solar data was used to identify open magnetic fields stretching from the lower corona to Earth orbit. 35 near-relativistic electron beams detected at the ACE spacecraft ?"labeled"? the heliospheric segments of the open fields. An X-ray flare occurred<20 minutes before injection of the electrons in 25 events. These flares labeled the solar segment of the open fields. The flares occurred in western-hemisphere active regions (ARs) with coronal holes whose polarity agreed with the polarity of the beam-carrying interplanetary fields in 23 of the 25 events. We conclude that electron beams reach 1 AU from open AR fields adjacent to flare sites. The Wang & Sheeley implementation of the potential-field source-surface model successfully identified the open fields in 36% of cases. Success meant that the open fields reached the source surface within 3 heliographic deg of the interplanetary magnetic field connected to ACE at 1 AU. Inclusion of five near misses improves the success rate to 56%. The success rate for the Schrijver & DeRosa PFSS implementation was 50%. Our results suggest that, even if the input magnetic data are updated frequently, the PFSS models succeed in only 50% of cases to identify the coronal segment of open fields. Development of other techniques is in its infancy.
Authors: Rust, D.M., Haggerty, D.K., Georgoulis, M.K., Sheeley, N.R., Wang, Y.-M., DeRosa, M.L., Schriver, C.J.
Projects: None
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Publication Status: in press, ApJ vol. 687
Last Modified: 2008-10-14 00:12
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