Occurrence Rate of Radio-Loud and Halo CMEs in Solar Cycle 25: Prediction Using their Correlation with the Sunspot Number

Abstract

The coronal mass ejections (CMEs) from the Sun are known for their space weather and geomagnetic consequences. Among all CMEs, so-called radio-loud (RL) and halo CMEs are considered the most energetic in the sense that they are usually faster and wider than the general population of CMEs. Hence the study of RL and halo CMEs has become important and the prediction of their occurrence rate in a future cycle will give a warning in advance. In the present paper, the occurrence rates of RL and halo CMEs in solar cycle (SC) 25 are predicted. For this, we obtained good correlations between the numbers of RL and halo CMEs in each year and the yearly mean sunspot numbers in the previous two cycles. The predicted values of sunspot numbers in SC 25 by NOAA/NASA were considered as representative indices and the corresponding numbers of RL and halo CMEs have been determined using linear relations. Our results show that the maximum number of RL and halo CMEs will be around 39 $/pm$ 3 and 45 $/pm$ 4, respectively. Removing backside events, a set of front-side events was also considered separately and the front-side events alone in SC 25 are predicted again. The peak values of front-side RL and halo events have been estimated to be around 31 $/pm$ 3 and 29 $/pm$ 3 respectively. These results are discussed in comparison with the predicted values of sunspots by different authors.