Relations between Coronal Mass Ejections and the Photospheric Magnetic Field in Cycles 23 and 24

The number of coronal mass ejections (CMEs) and their parameters and cycle variations were investigated and compared to the photospheric magnetic field evolution in cycles 23 and 24. The Coordinated Data Analysis Workshops (CDAW) catalog of white-light CMEs detected by the Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph coronagraphs and the data on the photospheric magnetic fields from the Kitt Peak Vacuum Telescope Spectromagnetograph (KPVT/Spectromagnetograph) and the Synoptic Optical Long-term Investigations of the Sun Vector-Spectromagnetograph (SOLIS/VSM) were used. The results suggest that not only did the number of CMEs increase in cycle 24, but that their parameters, cycle variations, distributions, and dependencies on the photospheric magnetic fields were also different. Various CME categories behave in different ways during solar cycles. The differences in the number and parameters of CMEs and their cycle variations may be related to the differences in the photospheric magnetic fields during the cycles. The strong photospheric magnetic fields maintained approximately the same strength from cycle 23 to cycle 24, whereas the weak fields became weaker and the area they occupied increased. Taking into account that the global magnetic field diminished from cycle 23 to cycle 24, the increase in the number of CMEs in cycle 24 can be understood. A detailed analysis of the similarities and differences in CME parameters and their cycle evolution indicates that, along with the influence of changes in the CME detection mode in 2004 and 2010, the changes in CME rate and parameters were also associated with real differences in the behavior of strong and weak photospheric magnetic fields in cycles 23 and 24.