Physical Science International Journal

This study examines the statistical relationship between solar flare classes and the occurrence of associated coronal mass ejections (CMEs) during solar cycles 23 and 24, covering the period from 1 January 1996 to 31 December 2019. The analysis considers CME angular width and speed, with CMEs grouped into narrow, normal, partial-halo, and full-halo categories. A total of 396 flare-associated CME events were considered, including 236 events during solar cycle 23 and 160 events during solar cycle 24. Among these events, 1 was associated with an A-class flare, 23 with B-class flares, 110 with C-class flares, 176 with M-class flares, and 86 with X-class flares.

The results show that M-class flares were the most frequently associated flare class across the CME categories. Narrow CMEs were mainly associated with M-class flares, while normal CMEs showed a broader distribution involving C-, M-, and X-class flares. Partial-halo CMEs were the dominant angular-width category in the dataset and were mostly associated with M-, C-, and X-class flares. No full-halo CME with an angular width of 360° was recorded in the analysed sample.

The speed distribution indicates that CMEs associated with M- and X-class flares were more frequently represented in higher-speed ranges, including events above 1500 km/s and, in some cases, above 2200 km/s. In the narrow-CME subset, the few X-class flare associations occurred only in the higher-speed categories. Overall, the results suggest that CME angular width alone does not determine CME speed or the intensity class of the associated solar flare. The findings should therefore be interpreted as a descriptive statistical assessment of flare-associated CME properties, while direct evaluation of CME geoeffectiveness would require additional in situ solar-wind and geomagnetic-response data.