Solar Wind Source Diversity as Revealed by its Composition
Abstract
The solar wind is a bimodal stream that is either called fast if it originates from coronal holes, or slow if it originates above the streamer belt. The two quasi-stationary modes are interspersed with transient streams with a duration of several hours to days that may differ radically in their properties: the coronal mass ejections. The stream types are traditionally defined by their kinetic and magnetic properties, perhaps supplemented (in the case of CMEs) by particle signatures. But over the last decade new instrumentation has added heavy ion composition as a diagnostic tool to describing the solar wind. We present the compositional signatures that are associated with the different stream types and the boundaries between them, and we show that in many cases they do more than just adding evidence to an otherwise clear-cut case. Compositional signatures identify stream interfaces, CMEs, or fast streams even in cases where the kinetic signatures are unclear. Moreover, they are a powerful tool for decoding the solar wind origin and acceleration: The charge states of heavy elements are indicative of the coronal temperature and its profile, whereas the elemental abundances probe the conditions and the processes in the chromosphere and lower transition region.
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2001
- Bibcode:
- 2001AGUSM..SH61B01V
- Keywords:
-
- 2164 Solar wind plasma;
- 2169 Sources of the solar wind;
- 7511 Coronal holes;
- 7513 Coronal mass ejections