1. Observations of the longitudinal spread of solar energetic particle events in solar cycle 24.
- Author
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Cohen, C.M.S., Mason, G.M., Wiedenbeck, M.E., Haggerty, D.K., Gomez-Herrero, R., Christian, E. R., Cummings, A.C., Korth, A., Labrador, A. W., Leske, R.A., Mall, U., Mewaldt, R.A., Stone, E.C., and Rosenvinge, T.T. Von
- Subjects
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SOLAR energetic particles , *SOLAR cycle , *SPACE vehicles , *QUANTITATIVE research , *CORONAL mass ejections , *HELIUM ions , *HYDROGEN ions - Abstract
With the twin STEREO spacecraft, significantly separated from L1-based satellites such as ACE, simultaneous multi-point measurements of solar energetic particle (SEP) events can be made for H-Fe ions from a few hundred keV/nuc to over 100 MeV/nuc and for electrons from tens to hundreds of keV. These observations allow studies of the longitudinal characteristics of SEP events to advance beyond statistical analysis of single point measurements. Although there have been few large SEP events thus far in cycle 24, there have been a number of smaller events that have been detected by more than one spacecraft. The composition of these SEP events, as indicated by the H/He and Fe/O abundance ratios, shows a dependence on longitudinal distance from the solar source in some events, at times with ratios varying by an order of magnitude. However, these variations are not organized by either the speed or width of the associated coronal mass ejections. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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