Study of Kinematic and Morphological Properties of CMEs

Margarita Karovska

Abstract

We present observations of several coronal mass ejections (CMEs) observed by the LASCO and EIT instruments onboard the Solar and Heliospheric Observatory.  These include CMEs having bright circular rims which can be interpreted as marking the apexes of expanding magnetic flux ropes. We have used image processing techniques to enhance features in these CMEs which can be tracked from their origins near the surface of the Sun out to great distances. One particularly interesting feature is the existence of sinuous lines below the circular rim, which in three dimensions may be helical in nature based on their appearance. We compared the kinematic and morphological properties of these CMEs with an MHD model of an erupting flux rope, and found they can be successfully modeled in this manner. Our results show that the acceleration of these CMEs takes place below heights of few solar radii and the velocity has leveled off as the CME reaches the LASCO/C3 field of view. We discuss the evidence that depending of there speed, the CMEs appear to be either gradually slowing down (fast CMEs), or gradually accelerating (slow CMEs), as they continue to propagate plowing through the solar wind.
 

       Authors: M. Karovska (CfA), B. E. Wood (JILA), J. Chen, J. W. Cook, R. A. Howard (NRL)

         Organization:  Harvard-Smithsonian Center for Astrophysics
            Telephone:  617 495 7347
                  Fax:  617 495 7356
               e-mail:  karovska@cfa.harvard.edu
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                        Cambridge, MA 02138
                        USA