Abstracts submitted by Pertti Makela
Halo coronal mass ejections and proton events during solar cycle 23
P. Makela[1,2]; N. Gopalswamy[2]; S. Yashiro[1,2]; S. Akiyama[1,2]; E. Valtonen [3]
[1] The Catholic University of America, Washington, DC, USA; [2] NASA Goddard Space Flight Center, Greenbelt, MD, USA; [3] Space Research Laboratory, University of Turku, Turku, Finland
We have studied the production and properties of solar energetic particles (SEPs) in association with halo coronal mass ejections (CMEs) during 1996-2005. A set of 378 halo CMEs observed by LASCO were compared with observations of the 1.8-80 MeV proton flux by ERNE, both instruments on board the SOHO spacecraft. The CME list included both frontside and backside halo CMEs. In general, particle production was observed to follow the known dependence on the position of solar source and the speed of the associated CME. Only a few of the backside CMEs were observed to coincided with proton events. In the case of frontside CMEs, a few CMEs with a speed less than 500 km/s produced detectable increase of interplanetary proton flux. There were fewer eastern hemisphere CMEs than western hemisphere CMEs associated with proton events. Similar kind of dependence for the geoeffectiveness of the same set of halo CMEs has been reported by Gopalswamy et al. 2007. We compare the source regions of geoeffective and SEPeffective halo CMEs. We finally discuss the properties of halos that were both geoeffective and SEPeffective. |
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