Coronal mass ejections acceleration problem

• Published in: Advances in space research Vol. 42; no. 5; pp. 852 - 857
• Main Authors: Wen, Yayuan, Wang, Jingxiu, Zhao, Hui, Filipe Maia, Dalmiro Jorge
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2008
• Subjects: Acceleration; Coronal mass ejections; Error estimates; Coronal mass ejections; Acceleration; Error estimates
• ISSN: 0273-1177; 1879-1948
• DOI: 10.1016/j.asr.2007.05.036

A statistical study of acceleration and its error of coronal mass ejections (CMEs) observed by the Large Angle Spectrometric Coronagraph (LASCO) is performed. A total of 5594 CMEs events have been analyzed by using a least-square method and using the error in the height measures. We verify that slower CMEs (velocities in the interval from 200 to 500 km s −1) tend to have a positive acceleration (about 1 m s −2) at heights above 5 solar radii, while less than 10% CMEs show an average negative acceleration (about −2.2 m s −2) as they propagate from 5 to 30 solar radii. For most individual CMEs one can not say if they are accelerated or decelerated, only for 8% of all observed CMEs events one can extract the sign of the acceleration in the 5–30 solar radii.