Three-Dimensional Properties of Coronal Mass Ejections from STEREO/SECCHI Observations

Abstract

We identify 565 coronal mass ejections (CMEs) between January 2007 and December 2010 in observations from the twin STEREO/SECCHI/COR2 coronagraphs aboard the STEREO mission. Our list is in full agreement with the corresponding SOHO/LASCO CME Catalog (http://cdaw.gsfc.nasa.gov/CME_list/) for events with angular widths of 45° and up. The monthly event rates behave similarly to sunspot rates showing a three- to fourfold rise between September 2009 and March 2010. We select 51 events with well-defined white-light structure and model them as three-dimensional (3D) flux ropes using a forward-modeling technique developed by Thernisien, Howard and Vourlidas (Astrophys. J. 652, 763-773, 2006). We derive their 3D properties and identify their source regions. We find that the majority of the CME flux ropes (82 %) lie within 30 ° of the solar equator. Also, 82 % of the events are displaced from their source region, to a lower latitude, by 25 ° or less. These findings provide strong support for the deflection of CMEs towards the solar equator reported in earlier observations, e. g. by Cremades and Bothmer (Astron. Astrophys. 422, 307-322, 2004). © 2012 The Author(s).