Charge States of Energetic Particles From Corotating Interaction Regions As Constraints On Their Source
- Creators
- Mazur, J. E.
- Mason, G. M.
- Mewaldt, R. A.
Abstract
Since the discovery of large (factor of greater than 1000) enhancements of singly ionized helium in corotating interaction regions (CIRs), it has become clear that low charge state ions from interstellar neutrals or other heliospheric sources can be preferentially injected into the energetic particle population. The large enhancements in suprathermal and energetic He suggest that low charge state ions may likewise affect the composition of CIR-related heavy ions such as C or Ne. Therefore, a key observational test of the contribution of pickup ions to the energetic particles associated with CIRs is their ionization state. We have used instrumentation on board the low Earth orbiting SAMPEX satellite, along with the geomagnetic cutoff technique, to investigate the ionization states of CIR heavy ions in the energy range 0.5-1.0 MeV nucleon^(-1). In a sum of 14 CIR events, we find heavy-ion charge states similar to those of solar energetic particles from interplanetary shocks, with upper limits to the contribution of singly ionized particles on the order of a few percent of the total flux. We find that stripping in the interplanetary medium of singly ionized heavy ions energized in the CIR could not account for the observed high charge states. Thus, the high charge state material we observed must have originated in the bulk solar wind or its suprathermal tail.
Additional Information
© 2002 The American Astronomical Society. Received 2001 May 25; accepted 2001 October 10. We thank the many members of the SAMPEX LICA instrument team who have contributed to the success of the SAMPEX mission, as well as the personnel at the Goddard Space Flight Center who constructed, launched, and operate the SAMPEX spacecraft. We appreciate discussions on ionization cross sections with A. F. Barghouty. Contract Z667103 between the University of Maryland and The Aerospace Corporation supported part of this work.Attached Files
Published - 2001-33.pdf
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Additional details
- Eprint ID
- 55440
- Resolver ID
- CaltechAUTHORS:20150302-163929283
- Aerospace Corporation
- Z667103
- Created
-
2015-03-06Created from EPrint's datestamp field
- Updated
-
2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Space Radiation Laboratory
- Other Numbering System Name
- Space Radiation Laboratory
- Other Numbering System Identifier
- 2001-33