A statistical study of the Cluster/CODIF observations of He+ energization in the magnetosphere
Abstract
It is well known that He+ can be resonantly energized by the electromagnetic ion cyclotron (EMIC) waves in the magnetosphere. The presence of both anisotropic energetic protons and heavy He+ ions is believed to be an important condition of the generation and propagation of the EMIC waves and the wave- particle interactions near the He+ gyrofrequency. From January 2001 to April 2008, the Composition and Distribution Function (CODIF) Analyzer on board the Cluster satellites observed 41 He+ energization events. In this study, we performed a statistical study of these He+ energization intervals. We report the statistical location of the intervals and the typical properties of H+ and the thermalizated He+ ions. In addition, the statistical results of the solar wind/interplanetary magnetic field (IMF) conditions and the levels of geomagnetic activity during the intervals are also presented.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFMSM33A1762Z
- Keywords:
-
- 2731 Magnetosphere: outer;
- 2740 Magnetospheric configuration and dynamics;
- 2772 Plasma waves and instabilities (2471);
- 2780 Solar wind interactions with unmagnetized bodies;
- 7867 Wave/particle interactions (2483;
- 6984)