A Caltech Library Service

Investigating the longitude dependence of solar energetic particle spectra

Cohen, C. M. S. and Mason, G. M. and Mewaldt, R. A. and Leske, R. A. (2012) Investigating the longitude dependence of solar energetic particle spectra. In: Space Weather: The Space Radiation Environment. AIP Conference Proceedings. No.1500. American Institute of Physics , Melville, N.Y., pp. 74-79. ISBN 978-0-7354-1114-2.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


We examine the traits of six solar energetic particle events observed simultaneously by instruments on ACE and at least one of the twin STEREO spacecraft. We compare the time profiles and spectra of energetic oxygen as a function of the longitudinal separation of the observer from the solar source region. We find systematic trends in the rise and peak times with source longitude that are consistent with those determined from single spacecraft studies. However, we also find two events where the rise times were surprisingly rapid when the source region was over the western limb relative to the observer. This has potential consequences for space weather predictions of radiation hazards. No clear trend is apparent for hardness of the event-integrated spectra with source longitude contrary to trends seen in the single spacecraft studies.

Item Type:Book Section
Related URLs:
URLURL TypeDescription
Cohen, C. M. S.0000-0002-0978-8127
Mason, G. M.0000-0003-2169-9618
Mewaldt, R. A.0000-0003-2178-9111
Leske, R. A.0000-0002-0156-2414
Additional Information:© 2012 American Institute of Physics. This work was supported by NASA under grants NNX08AI11G and NNX10AQ68G at Caltech, NNX10AT75G at JHUAPL, subcontracts SA2715-26309 from UC Berkeley (NASA contract NAS5-03131) and by NSF grant AGS-1156004. We thank Nariaki Nitta for useful discussions regarding solar source identifications.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Subject Keywords:Solar energetic particles, SEP composition, SEP spectra. solar wind, space vehicles
Series Name:AIP Conference Proceedings
Issue or Number:1500
Classification Code:PACS: 96.50.Vg, 96.60.Vg
Record Number:CaltechAUTHORS:20130117-081242064
Persistent URL:
Official Citation:Investigating the longitude dependence of solar energetic particle spectra C. M. S. Cohen, G. M. Mason, R. A. Mewaldt, and R. A. Leske AIP Conf. Proc. 1500, pp. 74-79; doi:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:36440
Deposited On:17 Jan 2013 17:19
Last Modified:09 Nov 2021 23:22

Repository Staff Only: item control page