Analysis of a Coronal Mass Ejection and a Co-rotating Interaction Region as they travel from the Sun, passing Venus, Earth, Mars and Saturn |
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Ailsa Prise Submitted: 2015-04-21 07:40
During June 2010 a good alignment in the solar system between Venus, STEREO-B, Mars and Saturn provided an excellent opportunity to study the propagation of a Coronal Mass Ejection (CME) and closely occurring Co-rotating Interaction Region (CIR) from the Sun to Saturn. The CME erupted from the Sun at 01:30 UT on 20 June 2010, with v~600 km s-1, as observed by STEREO-B, SDO and SOHO/LASCO. It arrived at Venus over 2 days later, some 3.5 days after a CIR is also detected here. The CIR was also observed at STEREO-B and Mars, prior to the arrival of the CME. The CME is not directed Earthward, but the CIR is detected here less than 2 days after its arrival at Mars. Around a month later, a strong compression of the Saturn magnetosphere is observed by Cassini, consistent with the scenario that the CME and CIR have merged into a single solar transient. The arrival times of both the CME and the CIR at different locations were predicted using the ENLIL with cone model. The arrival time of the CME at Venus, STEREO-B and Mars is predicted to within 20 hours of its actual detection, but the predictions for the CIR showed greater differences from observations, all over 1.5 days early. More accurate predictions for the CIR were found by extrapolating the
travel time between different locations using the arrival times and speeds detected by STEREO-B and ACE. We discuss the implications of these results for understanding the
propagation of solar transients.
Authors: A. J. Prise, L. K. Harra, S. A. Matthews, C. S. Arridge, N. Achilleos
Projects: ACE,Other,SDO-AIA,SoHO-LASCO,STEREO
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Publication Status: Published
Last Modified: 2015-04-21 10:44
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An Investigation of the CME of 3 November 2011 and its Associated Widespread Solar Energetic Particle Event |
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Ailsa Prise Submitted: 2013-11-14 10:01
Multi-spacecraft observations are used to study the in-situ effects of a large CME erupting from the farside of the Sun on 3 November 2011, with particular emphasis on the associated solar energetic particle (SEP) event. At that time both Solar Terrestrial Relations Observatory (STEREO) spacecraft were located more than 90 degrees from Earth and could observe the CME eruption directly, with the CME visible on-disk from STEREO-B and off the limb from STEREO-A. Signatures of pressure variations in the corona such as deflected streamers were seen, indicating the presence of a coronal shock associated with this CME eruption. The evolution of the CME and an associated EUV wave were studied using EUV and coronagraph images. It was found that the lateral expansion of the CME low in the corona closely tracked the propagation of the EUV wave, with measured velocities of 240?19 km s-1 and 221?15 km s-1 for the CME and wave respectively. Solar energetic particles were observed arriving first at STEREO-A, followed by electrons at the Wind spacecraft at L1, then STEREO-B, and finally protons arriving simultaneously at Wind and STEREO-B. By carrying out velocity-dispersion analysis on the particles arriving at each location, it was found that energetic particles arriving at STEREO-A were released first and the release of particles arriving at STEREO-B was delayed by around 50 minutes. Analysis of the expansion of the CME to a wider longitude indicates that this delay is a result of the time taken for the edge of the CME to reach footpoints of the magnetic-field lines connected to STEREO-B. The CME expansion is not seen to reach the magnetic footpoint of Wind at the time of solar particle release for the particles detected here, suggesting that these particles may not be associated with this CME.
Authors: A. J. Prise, L. K. Harra, S. A. Matthews, D. M. Long, A. D. Aylward
Projects: None
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Publication Status: Solar Physics (in press)
Last Modified: 2013-11-17 13:30
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