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The roles of flares and shocks in determining sep abundances
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | vonRosenvinge, T. T. Cohen, C. M. S. Mewaldt, R. A. Cane, H. V. |
| Copyright Year | 2007 |
| Description | We examine solar energetic particle (SEP) event-averaged abundances of Fe relative to O and intensity versus time profiles at energies above 25 MeV/nucleon using the SIS instrument on ACE. These data are compared with solar wind conditions during each event and with estimates of the strength of the associated shock based on average travel times to 1 AU. We find that the majority of events with an Fe to 0 abundance ratio greater than two times the average 5-12 MeV/nuc value for large SEP events (0.134) occur in the western hemisphere. Furthermore, in most of these Fe-rich events the profiles peak within 12 hours of the associated flare, suggesting that some of the observed interplanetary particles are accelerated in these flares. The vast majority of events with Fe/O below 0.134 are influenced by interplanetary shock acceleration. We suggest that variations in elemental composition in SEP events mainly arise from the combination of flare particles and shock acceleration of these particles and/or the ambient medium. |
| File Size | 1350166 |
| Page Count | 19 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20070018209 |
| Archival Resource Key | ark:/13960/t2k69fs0s |
| Language | English |
| Publisher Date | 2007-01-01 |
| Access Restriction | Open |
| Subject Keyword | Solar Physics Wind Direction Solar Flares Interplanetary Shock Waves Western Hemisphere Wind Velocity Abundance Solar Corpuscular Radiation Iron Solar Wind Energetic Particles Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
