29 July 2015 to 6 August 2015
World Forum
Europe/Amsterdam timezone

The Longitudinal Distribution of Solar Energetic Particles

30 Jul 2015, 11:00
Mississippi (World Forum)


World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
Oral contribution SH-EX Parallel SH 01 SEP I


Tycho von Rosenvinge (NASA/Goddard Space Flight Center)


Using observations from the High Energy Telescopes on STEREO A and B and similar observations from SoHO, near-Earth, we have identified ~250 individual solar energetic particle events that include >14 MeV protons since the beginning of the STEREO mission (Richardson, et al., Solar Physics, 2014). Between the end of December 2009, when the STEREO A and B spacecraft were, respectively, ahead and behind Earth by ~ 65° in ecliptic longitude, and the end of December 2013, 43 different events were clearly detected at all three locations. The observed intensities of such an event are usually fit with a Gaussian which is a function of the longitudes of the Parker Spiral footpoints at the Sun for each observer. This neglects the fact that the interplanetary magnetic field may have large deviations from Parker Spirals, e.g. due to coronal mass ejections from prior events. Nonetheless, we have fit Gaussians to the peak intensities observed simultaneously at three spacecraft for all 43 events, taking into account particles coming around the Sun both from the east and from the west. The Gaussian peak intensity is poorly correlated with the corresponding CME speed and the FWHM is uncorrelated with the CME speed. Surprisingly, however, there appear to be distinctly non-random variations of the FWHM values from event to event. We will investigate possible causes of this effect.
Collaboration -- not specified --
Registration number following "ICRC2015-I/" 564

Primary author

Tycho von Rosenvinge (NASA/Goddard Space Flight Center)


Alan Cummings (California Institute of Technology) Allan Labrador (California Institute of Technology) Christina Cohen (California Institute of Technology) Edward Stone (California Institute of Technology) Eric Christian (NASA/Goddard Space Flight Center) Hilary Cane (U of Tasmania) Ian Richardson (NASA/Goddard Space Flight Center) Mark Wiedenbeck (Jet Propulsion Laboratory) Richard Leske (California Institute of Technology) Richard Mewaldt (California Institute of Technology)

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