The soft X-ray characteristics of solar flares, both with and without associated CMEs

Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey, RH5 6NT, UK

Corresponding author: H. R. M. Kay, hrm@mssl.ucl.ac.uk

Received: 9 December 2002
Accepted: 9 January 2003

Abstract

The complex relationship between solar flares and coronal mass ejections is investigated using a comparison of flare parameters for a total of 69 ejective and non-ejective flares. In the case of solar flares which do not show mass ejection there seems to be a clear relationship between the peak intensity and duration, with higher intensity events being of longer duration. Systematic differences in the relationship between peak temperature and intensity for the two types of event are also evident, with flares associated with CMEs tending to have lower peak temperatures than non-ejective events of the same intensity. Whilst there appears to be a clear relationship between the length of rise and decay phase in a flare, there are no systematic differences in these parameters for ejective and non-ejective flares. A total of eleven “EIT waves” were found, all of which were associated with CMEs. There is no apparent correlation between the occurrence of an EIT wave and the peak temperature, intensity or rise time of the associated flare.