1. Sources of solar energetic particles revealed by composition data
The charge compositions of solar energetic particles (SEPs) reflect the properties of their source regions and acceleration process.
SEPICA on ACE has observed a wide variety of SEP charge distributions. Two examples, from a gradual and an impulsive event, are shown in the left-hand side of the figure.
The solar wind charge state distribution, as measured by SWICS-ACE, shows similarly diverse distributions. The right-hand side of the figure shows data from two CME periods.
These compositional patterns are used to trace solar energetic particles and solar wind plasma to their respective source in the solar corona and determine the physical conditions in their respective acceleration regions.
Contributed by Thomas Zurbuchen, University of Michigan, and Mark Popecki, University of New Hampshire. 1