Mewaldt, R. A. and Mason, G. M. and Cohen, C. M. S. and Gómez-Herrero, R. and Haggerty, D. K. and Leske, R. A. and Wiedenbeck, M. E. (2012) Evolution of suprathermal seed particle and solar energetic particle abundances. In: Physics of the heliosphere: a 10 year retrospective. AIP Conference Proceedings (1436). American Institute of Physics , Melville, NY, pp. 206-211. ISBN 978-0-7354-1026-8 http://resolver.caltech.edu/CaltechAUTHORS:20120529-082347635
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We report on a survey of the composition of solar-wind suprathermal tails and solar energetic particles (SEPs) including data from 1998 to 2010, with a focus on 2007 to 2010. The start of solar cycle 24 included several SEP events that were unusually He-poor. We conclude that these He-poor events are more likely related to Q/M-dependent spectral variations than to seed-particle composition changes. We also find that the quiet-time suprathermal Fe/O ratio during the 2008-2009 solar-minimum was dramatically lower (Fe/O ≤ 0.01) than earlier due in part to very low solar activity, but also suggesting contributions from an oxygen-rich source of suprathermal ions of unknown origin.
|Item Type:||Book Section|
|Additional Information:||© 2012 American Institute of Physics. NASA funded this work under grant NNX10AT75G at JHU/APL, and at Caltech under grants NNX08AI11G, NNX10AE45G, and subcontract SA2715-26309 from UC Berkeley under NASA contract NAS5-03131. We thank Eberhard Möbius and Nathan Schwadron for helpful discussions.|
|Group:||Space Radiation Laboratory|
|Subject Keywords:||Solar energetic particles, solar wind, pickup ions, solar composition, solar flares|
|Classification Code:||PACS: 96.50.Vg, 96.60.Vg, 96.60.Q-, 96.50.Pw, 96.60.P-, 96.60.Qe|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||08 Jun 2012 18:14|
|Last Modified:||28 Feb 2013 21:31|
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