Asian Basic and Applied Research Journal

Coronal Mass Ejections (CMEs) are primary drivers of space weather, yet their propagation dynamics remain poorly constrained across different solar cycles (SCs) and angular width (AW) regimes. This study presents a comparative analysis of narrow (≤30°), normal (30° < AW < 120°), and wide (≥120°) CMEs across SCs 23 and 24 using SOHO/LASCO observations spanning 1996–2019. We find that SC 24 CMEs are systematically slower, less massive, and exhibit reduced AWs compared with SC 23. Peak linear speeds in SC 23 reached 961 km/s for wide CMEs (year 8) versus only 687 km/s in SC 24 (year 4)—a 28% reduction. Similarly, peak CME kinetic energy dropped from 9.37 x 10³¹  J in SC 23 to 2.2.99 x 10³¹ J in SC 24, while the maximum CME mass decreased from 2.8×10¹⁵ g to 1.8×10¹⁵ g. Statistical analysis reveals contrasting distributional characteristics: SC 24 narrow CMEs exhibit extreme leptokurtosis (mass kurtosis = 16.38 vs. 2.76 in SC 23), indicating rare high-mass outliers absent in the previous cycle. Most significantly, we identify an anomalous propagation behaviour for 120° CMEs in SC 24, with arrival times of 4.43 days compared with 0.88 days for equivalent SC 23 events—a 400% increase. To explain this, we develop a semi-analytical propagation model incorporating cycle-dependent variability (γ) and dissipation (δ) parameters. The model achieves good predictive estimates of arrival time (RMSE = 1.34 hours, R² = 0.99874) across diverse validation events, including Bastille Day and Halloween Storm events. We demonstrate that the 120° anomaly could arise from coupled effects: higher drag (δ = 0.35 day⁻¹) and reduced expansion efficiency (γ = 0.80) in SC 24, which produce stronger deceleration for intermediate-width CMEs. These findings demonstrate that AW is a fundamental predictor of CME evolution, but forecasting models require cycle-specific parameterisation. Our framework provides a plausible, physically consistent foundation for operational space weather forecasting and highlights the critical role of heliospheric conditions in modulating CME geoeffectiveness.