Are Inner Source Pickup Ions further Accelerated in Interplanetary Space?
Abstract
Inner source pickup ions originate most likely from the interaction of the solar wind with dust particles in interplanetary space. They are thought to be generated either through saturation of dust with solar wind, subsequent desorption, and pickup, or through penetration of small dust grains by solar wind, neutralization, and subsequent re-ionization. In both cases a velocity distribution emerges, which is genuinely suprathermal, but peaks below the solar wind speed. Based on the realization that interstellar pickup ions are preferentially injected for further acceleration it has been suggested that also inner source ions may contribute visibly to the energetic particle populations in interplanetary space. It has been shown that inner source ions do not contribute significantly to the CIR population that is accelerated mostly outside 1 AU and observed in Earth's orbit. Since inner source ions are generated close to the sun one might expect that they could contribute to energetic particles accelerated at traveling shocks. We will present results from the search of such ions in traveling shocks that have been identified to accelerate substantial amounts of He+. The results will be discussed in the light of models for inner source pickup ion distributions and for injection of ions into acceleration.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2004
- Bibcode:
- 2004AGUFMSH43B..07M
- Keywords:
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- 2109 Discontinuities;
- 2114 Energetic particles;
- heliospheric (7514);
- 2129 Interplanetary dust;
- 2152 Pickup ions