Nonlinear and Causal Dynamics between Solar and Geomagnetic Activity Indices: Findings from Chaos and Causality Measures
Year: 2025
Type: conference-paper
Abstract: This study aims to identify nonlinear/chaotic features and causal relationships among monthly SSN, F10.7, aa, and Dst indices over December 1963-March 2025.Phase-space is reconstructed via AMI-selected delay 𝜏 and FNN dimension 𝐸; we estimate the Hurst exponent 𝐻, the largest Lyapunov exponent 𝜆, and the correlation dimension 𝐷 2 ; and apply CCM with SSN as reference.𝐻 spans 0.84-0.93(𝑆𝑆𝑁 ≈ 0.93; 𝐹10.7 ≈ 0.93; 𝑎𝑎 ≈ 0.88; 𝐷𝑠𝑡 ≈ 0.84), indicating strong persistence.𝜆 ranges from ≈ 0.010 to ≈ 0.040 (highest for Dst, lowest for aa), implying deterministic chaos with finite prediction horizons.𝐷 2 varies between 3.37-3.86,consistent with low-moderate dimensional structure.CCM analysis shows a strong linear relationship between SSN-F10.7, while indicating a non-linear causal relationship between SSN and other indices.In conclusion, sunspot variability affects global geomagnetic activity continuously and nonlinearly on a monthly scale; this effect is most pronounced for aa and weaker for Dst.
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W4415218296
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