Statistical Analysis of Coronal Mass Ejection (CME) Angular Widths Across Solar Cycles 23 and 24

This study investigates the relationship between coronal mass ejection (CME) parameters and sunspot metrics—sunspot number (SSN) and sunspot area (SSA)—across Solar Cycles (SCs) 23 and 24, with a focus on narrow, normal, and wide CMEs. Results indicate that CME dynamics vary significantly with angular width: narrow and wide CMEs are more strongly influenced by solar wind and interplanetary medium conditions, whereas normal CMEs exhibit a more complex interaction with sunspot activity. Histogram distributions of linear speed show that narrow, normal, and wide CMEs predominantly fall within 300–400 km/s, 400–500 km/s, and 500–700 km/s, respectively, with wide CMEs displaying greater variability, especially during SC 23. CME speeds peak during solar maximum (years 6–8 of the cycle), and while narrow CMEs are the most frequent, they are generally less geoeffective unless interacting with corotating interaction regions (CIRs). The lower occurrence rate of wide CMEs supports the rarity of extreme solar eruptions. Right-skewed speed distributions indicate that a fraction of wide CMEs reach extreme velocities (> 1000 km/s), often associated with major space weather events. Speed measurements at 20 R _⊙ confirm significant deceleration due to solar wind drag, particularly in SC 24 and among narrow CMEs. The convergence of mean and median speeds at this distance suggests that extremely fast CMEs slow down substantially, shortening the distribution's high-speed tail. Size analyses show that narrow CMEs typically maintain angular widths below 30°, while normal CMEs cluster around 50° in SC 23 and 40° in SC 24. Wide CMEs exhibit the broadest angular spread, with SC 23 generating more expansive and massive events. A notable mass reduction for wide CMEs in SC 24 points to a decline in large-scale, high-mass eruptions during this weaker cycle. To complement these statistical findings, a physics-based numerical model was developed to simulate CME propagation under varying solar conditions. The model integrates Lorentz and drag forces, magnetic pressure gradients, and rotational dynamics, offering insights into the physical processes driving observed variability. Together, the empirical analysis and modeling results provide a more comprehensive understanding of CME behavior and its dependence on angular width and solar cycle phase.