Electrons and Protons in Solar Energetic Particle Events
Abstract
A plot of 0.5 MeV peak electron intensity vs. 10 MeV peak proton intensity for well-connected (W20-90) solar energetic particle (SEP) events from 1997-2003 reveals two distinct populations: (1) a group of events with peak proton intensities < 3 pr cm-2 s-1 sr-1 that have electron to proton (e/p) ratios ranging from 3 x 102 - 5 x 104, and (2) a branch spanning peak proton intensities from 3 - 104 pr cm-2 s-1 sr-1 with e/p ratios ranging from 102 - 3 x 102. Events with strong trans-Fe enhancements form a prominent subset of "population 1" and are absent from "population 2". The SEP events in population 2 are highly ( 85%) associated with decametric/hectometric type II bursts vs. only a 15% association rate for events with trans-Fe enhancements in population 1. For a sample of poorly-connected (E40-W19 and W91-W150) SEP events, population 1 largely disappears, and population 2 is observed to extend down to low (< 10-1 pr cm-2 s-1 sr-1) proton intensities. These results are discussed in terms of current thinking on particle acceleration at the Sun.
- Publication:
-
AAS/Solar Physics Division Meeting #37
- Pub Date:
- June 2006
- Bibcode:
- 2006SPD....37.2902C