Variability of solar eruptions during cycle 23 Original Research Article

We report on the solar cycle variation of the rate of coronal mass ejections (CMEs), their mean and median speeds, and the rate of type II radio bursts. We found that both CME rate and speed (mean and median) increased from solar minimum to maximum by factors of 10 and 2, respectively. The CME rate during solar maximum is nearly twice the rates quoted previously. Large spikes in the speed variation were due to active regions that were highly active. The poor correlation between metric and DH type II bursts is confirmed, and the difference is attributed to the different Alfven speeds in the respective source regions.