Self-Organized Criticality Across Thirteen Orders of Magnitude in the Solar-Stellar Connection

2025/03/23 by Aschwanden, Markus J., Carolus, Schrijver, J.
#FOS: Physical sciences #Solar and Stellar Astrophysics (astro-ph.SR)

paper · doi:10.48550/arxiv.2503.18136

Abstract

The observed size distributions of solar and stellar flares is found to be consistent with the predictions of the fractal-diffusive self-organized criticality (FD-SOC) model, which predicts power law slopes with universal constants of α_F=(9/5)=1.80 for the flux, and α_E=(5/3)≈ 1.67 for the fluence, respectively. In this Letter we explore the solar-stellar connection under this aspect, which extends over an unprecedented dynamic range of 13 orders of magnitude between the smallest detected solar nanoflare event (E_min=10²⁴ erg) and the largest superflare (E_max=10³⁷ erg) on solar-like G-type stars, observed with the KEPLER mission. The FD-SOC model predicts a scaling law of L ∝ E^(2/9) for the length scale L as a function of the flare energy E, which limits the largest flare size to L_max \lapprox 0.14 R_\odot for solar flares, and L_stellar \lapprox 1.04 R_\odot for stellar flares on G-type stars. In the overall we conclude that the universality of power laws (and their slopes) is a consequence of SOC properties (fractality, classical diffusion, scale-freeness, volume-flux proportionality), rather than identical physical processes at different wavelengths.

Related

• Universal Constants and Energy Integral in Self-Organized Criticality Systems
• Testing the Universality of Self-Organized Criticality in Galactic, Extra-Galactic, and Black-Hole Systems
• Power Laws Associated with Self-Organized Criticality: A Comparison of Empirical Data with Model Predictions
• A Universal Scaling Law for the Fractal Energy Dissipation Domain in Self-Organized Criticality Systems
• Interface Region Imaging Spectrograph (IRIS) Observations of the Fractal Dimension in the Solar Atmosphere