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A novel technique to infer ionic charge states of solar energetic particles

Sollitt, L. S. and Stone, E. C. and Mewaldt, R. A. and Cohen, C. M. S. and Cummings, A. C. and Leske, R. A. and Wiedenbeck, M. E. and von Rosenvinge, T. T. (2008) A novel technique to infer ionic charge states of solar energetic particles. Astrophysical Journal, 679 (1). pp. 910-919. ISSN 0004-637X. doi:10.1086/587121.

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In some large solar energetic particle (SEP) events, the intensities of higher energy SEPs decay more rapidly than at lower energies. This energy dependence varies with particle species, as would be expected if the decay timescale depended on a rigidity-dependent diffusion mean free path. By comparing the decay timescales of carbon, nitrogen, oxygen, neon, magnesium, silicon, sulfur, and iron, mean charge states are inferred for these (and other) elements in three SEP events between 1997 and 2002 at energies between 10 and 200 MeV nucleon−1. In a fourth event, upper limits for the charge states are inferred. The charge states of many different particle species are all consistent with a single source temperature; in two events in 1997 and 2002, the best-fit temperature is much higher than that of the corona, which could imply a contribution from solar flare material. However, comparison with lower energy iron charge states for the 1997 event implies that the observed high-energy charge state could also be understood as the result of stripping during shock acceleration in the corona.

Item Type:Article
Related URLs:
URLURL TypeDescription
Stone, E. C.0000-0002-2010-5462
Mewaldt, R. A.0000-0003-2178-9111
Cohen, C. M. S.0000-0002-0978-8127
Cummings, A. C.0000-0002-3840-7696
Leske, R. A.0000-0002-0156-2414
Additional Information:© 2008 American Astronomical Society. Received 2006 December 8; accepted 2008 January 28. This work was supported by NASA at Caltech, JPL, and GSFC under grants NAG5-6912 and NAG5-12929.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Subject Keywords:acceleration of particles; methods: data analysis; Sun: particle emission
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Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2008-02
Issue or Number:1
Record Number:CaltechAUTHORS:SOLapj08
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:12481
Deposited By: Tony Diaz
Deposited On:13 Dec 2008 00:36
Last Modified:08 Nov 2021 22:29

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