2021/02/03 by Markus J. Aschwanden, Thierry Dudok de Wit
Earth and Planetary Sciences · Mathematics · Physics and Astronomy · #Astrophysics #Atmospheric sciences #Coronal mass ejection #Earthquake Detection and Analysis #Magnetic field #Mathematics #Meteorology #Physics #Power law #Solar and Space Plasma Dynamics #Solar cycle #Solar flare #Solar irradiance #Solar maximum #Solar minimum #Solar wind #Statistical Mechanics and Entropy #Statistics #Sunspot #astro-ph.SR
paper · pdf · doi:10.3847/1538-4357/abef69
published as (2021), ApJ 912:94 · 12 pages, 8 figures
arxiv created 2021/02/03 · openalex publication_date 2021/05/01 · arxiv updated 2021/06/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract Waiting-time distributions of solar flares and coronal mass ejections (CMEs) exhibit power-law-like distribution functions with slopes in the range of α τ ≈ 1.4–3.2, as observed in annual data sets during four solar cycles (1974–2012). We find a close correlation between the waiting-time power-law slope α τ and the sunspot number (SN), i.e., α τ = 1.38 + 0.01 × SN. The waiting-time distribution can be fitted with a Pareto-type function of the form N ( τ ) = N 0 , where the offset τ 0 depends on the instrumental sensitivity, the detection threshold of events, and pulse pileup effects. The time-dependent power-law slope α τ ( t ) of waiting-time distributions depends only on the global solar magnetic flux (quantified by the sunspot number) or flaring rate, which is not predicted by self-organized criticality or magnetohydrodynamic turbulence models. Power-law slopes of α τ ≈ 1.2–1.6 were also found in solar wind switchback events, as observed with the Parker Solar Probe during the solar minimum, while steeper slopes are predicted during the solar maximum. We find that the annual variability of switchback events in the heliospheric solar wind and solar flare and CME rates (originating in the photosphere and lower corona) are highly correlated.