A Comparison of Solar Energetic Particle Events with 1 AU Magnetic Field Connections to Solar Coronal Holes
Abstract
The observed properties of solar energetic particle (SEP) events are known to depend on the source locations and speeds of their associated coronal mass ejections (CMEs). However, the CME characteristics cannot account for a great deal of the variability in SEP event intensities and time scales. It has long been suspected that the presence of coronal holes (CHs) near the CMEs or near the 1 AU magnetic footpoints may be an important factor in SEP events. We use a group of E 20 MeV SEP events with origins near solar central meridian to look for possible CH effects. The CH connections from 1 AU are determined from the 4-day forecast maps based on Mount Wilson Observatory and the National Solar Observatory synoptic magnetic field maps and the Wang-Sheeley-Arge model of solar wind propagation. The observed in situ magnetic field polarities and solar wind speeds at SEP event onsets test the forecast accuracies to select the best SEP/CH connection events for analysis. The SEP event properties are then compared with the relative locations and separations of the CMEs and the 1 AU footpoints to determine whether and how the CHs may affect SEP events.
- Publication:
-
American Astronomical Society Meeting Abstracts #220
- Pub Date:
- May 2012
- Bibcode:
- 2012AAS...22020436K