Solar activity and the associated ground level enhancements of solar cosmic rays during solar cycle 23
07 Oct 2011
1Physics Department, National and Kapodistrian University of Athens, 15771 Athens, Greece
2INAF-Istituto di Fisica dello Spazio Interplanetario, Roma, Italy
3Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Science, Moscow, Russia
Abstract. The solar cycle 23 seems to be of great interest for the researchers due to many peculiarities. A study of the parameters of the sixteen ground level enhancements recorded during the approximately 12-year period of it (1996–2008) together with the associated solar activity, including the main properties of the solar flares, the coronal mass ejections and the radio bursts has been realized, in an effort to understand the connection of these events. All studied cases seem to be connected with very intense flares of long duration, having a mean importance value of X5.9 and a mean duration of 164.5 min, with either halo or partial halo coronal mass ejections with a mean linear velocity of 1876 km/sec, as well as with intense radio bursts. It is also noticed that the ground level enhancements of the 23rd solar cycle occurred after the onset time of the associated solar X-ray flares with a mean time delay of about 38 min, very useful result for their monitoring and prediction.