2023/06/25 by Reynan Toledo, Toledo, Reynan L., Reinabelle Reyes +3
Physics and Astronomy · #60 #FOS: Physical sciences #Solar and Space Plasma Dynamics #Solar and Stellar Astrophysics (astro-ph.SR) #Space Physics (physics.space-ph)
paper · pdf · doi:10.48550/arxiv.2306.14151
openalex publication_date 2023/06/25 · openalex created_date 2023/06/28 · openalex updated_date 2026/07/28
The rise and fall in the number of sunspots have served as a lynchpin in many investigations on solar dynamics. Arising from magnetic disturbances in the sun, variations in sunspot numbers have helped define a solar cycle of around eleven years which to date is yet to be fully understood. We model the fluctuation of sunspot numbers as a modulated Brownian motion characterized by a memory parameter μ and a decay parameter \beta. By matching the theoretical and empirical mean square deviation of the sunspot numbers, the values of μ and \beta are determined for each solar cycle. This allows us to obtain an exact form of a probability density function (PDF) which closely matches the dataset for sunspots. This novel PDF for sunspot numbers exhibit a memory behavior from which some insights could be obtained. In particular, the values of μ indicate that consecutive sunspot numbers are negatively correlated for large times. The values of \beta, on the other hand, when viewed as a time series from one solar cycle to another, indicate a positive trend towards increasing values which could possibly suggest a diminishing solar activity.