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STEREO and ACE Observations of Energetic Particles from Corotating Interaction Regions

Leske, R. A. and Mewaldt, R. A. and Mason, G. M. and Cohen, C. M. S. and Cummings, A. C. and Labrador, A. W. and Stone, E. C. and Wiedenbeck, M. E. and von Rosenvinge, T. T. (2010) STEREO and ACE Observations of Energetic Particles from Corotating Interaction Regions. In: Twelfth International Solar Wind Conference. AIP Conference Proceedings . No.1216. American Institute of Physics , Melville, NY, pp. 379-382. ISBN 978-0-7354-0759-6.

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Since early 2007, significant particle enhancements due to corotating interaction regions (CIRs) have regularly appeared at 1 AU without any appreciable contamination from solar energetic particles (SEPs). In 2009 the prevalence of CIRs diminished as the maximum speed of the high speed solar wind streams in the ecliptic decreased along with the tilt of the heliospheric current sheet. Observations of CIR time profiles at different longitudes from STEREO show delays between the Behind and Ahead spacecraft that are often roughly as expected from the corotation time lag, although small differences in the spacecraft latitudes introduce significant scatter in the time delays. In some cases different features seen at Ahead and Behind suggest that transient disturbances in the solar wind may alter connection to or transport from the shock, or that temporal changes occur in the CIR shock itself. H and He data from STEREO/LET at 1.8–6 MeV/nucleon show that 1) the CIR spectral index at these energies is ~−4, independent of intensity but with considerable variability, 2) the He/H ratio is ~0.03 for larger CIRs but varies systematically with energy and event intensity, and 3) although the correlation between the CIR MeV particle increases and solar wind speed is generally good, many times a high-speed stream is not associated with MeV particles, while at other times a recurring series of CIR particle increases appears only at higher energies and may be associated with current sheet crossings and low speed solar wind.

Item Type:Book Section
Related URLs:
Leske, R. A.0000-0002-0156-2414
Mewaldt, R. A.0000-0003-2178-9111
Mason, G. M.0000-0003-2169-9618
Cohen, C. M. S.0000-0002-0978-8127
Cummings, A. C.0000-0002-3840-7696
Labrador, A. W.0000-0001-9178-5349
Stone, E. C.0000-0002-2010-5462
Wiedenbeck, M. E.0000-0002-2825-3128
Additional Information:© 2010 American Institute of Physics. Issue Date: 25 March 2010. This work was supported by NASA at Caltech and JPL under sub-contract SA2715-26309 from UC Berkeley under NASA contract NAS5-03131. We thank STEREO/PLASTIC (NASA contract NAS5-00132), STEREO/MAG, and ACE/SWEPAM investigators for making their data publicly available.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Subject Keywords:Interplanetary physics; Corotating streams; Energetic particles; STEREO; ACE
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Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2010-09
Series Name:AIP Conference Proceedings
Issue or Number:1216
Classification Code:PACS: 96.60.Vg; 94.05.Hk; 96.50.S-; 96.60.Hv
Record Number:CaltechAUTHORS:20100921-082613682
Persistent URL:
Official Citation:STEREO and ACE Observations of Energetic Particles from Corotating Interaction Regions R. A. Leske, R. A. Mewaldt, G. M. Mason, C. M. S. Cohen, A. C. Cummings, A. W. Labrador, E. C. Stone, M. E. Wiedenbeck, and T. T. von Rosenvinge, AIP Conf. Proc. 1216, 379 (2010), DOI:10.1063/1.3395881
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:20056
Deposited By: Tony Diaz
Deposited On:24 Sep 2010 21:42
Last Modified:08 Nov 2021 23:57

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