Understanding the Longitudinal Extent and Timing of SEP Onsets: The November 3 2011 Event
Abstract
We study a multi-spacecraft solar energetic particle (SEP) event, which occurred on November 3 2011. The CME associated with the SEP event was observed as a behind the east-limb event (N06E152) by SOHO/LASCO. The CME was observed to be at W102 and E50 in STEREO-A and B views, respectively. This SEP event had a remarkable prompt particle increase at all three spacecraft despite their wide separation. Using a forward-fitting technique with an oblate spheroid model, we study the evolution of the CME shock and EUV wave in the low corona. Observations from STEREO and SOHO (white light), and SDO (EUV) were used to constraint the 3D shock shape and the EUV imprints on the solar surface. The combination of a full 3D model and multi-wavelength observational constraints allowed us to determine the radial and expansion speeds of the CME-shock and EUV wave in a consistent way. We were also able to determine the timing and the locations where the shock front intersects the magnetic footpoints connected to each spacecraft. The Parker-spiral theory with the average solar-wind speed measured in situ was used to estimate the location of magnetic field lines connecting the Sun to each spacecraft. The SEP onset time was determined by carrying out a velocity-dispersion analysis on the particles arriving at each spacecraft. By comparing the SEP onset delay with the time taken for the shock to expand to the longitudes of the connecting magnetic field lines, we confirmed that the wide spread SEP event was in fact a result of the expanding shock and the EUV wave for this case.
- Publication:
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Solar Heliospheric and INterplanetary Environment (SHINE 2014)
- Pub Date:
- June 2014
- Bibcode:
- 2014shin.confE..86X