STEREO observations of suprathermal electron distributions and the solar cycle variation of the interplanetary field
Abstract
STEREO SWEA provides the opportunity to observe solar wind halo electron heat fluxes and strahl over 4pi steradians at locations free of Earth bow shock contamination. After 4+ years of observations, and with the onset of solar cycle 24, we can begin to take a detailed look at the pitch angle distributions related to coronal transients impactng the interplanetary flux budget. Of primary interest are the conditions that lead to hour-scale, strong electron heat fluxes pointed back toward the Sun and counterstreaming or bi-directional electrons. Both of these phenomena have been associated with dynamical reconfigurations of the coronal fields, and in the case of counterstreaming, with the addition of magnetic flux to the heliosphere. We reconsider the different types of behavior known to be present in and around ICMEs from previous studies. Our analyses suggest how ICMEs enable the observed cycle variation in the interplanetary field strength. In particular, we show how counterstreaming can correspond to both the opening and closing of magnetic flux rooted at the Sun when other source(s) of suprathermals are considered.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFMSH21A1906E
- Keywords:
-
- 7536 SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY / Solar activity cycle