Quantifying Turbulence as Captured in the Inner Corona in White-light Total Solar Eclipse Images

Abstract Turbulence is a fundamental process in astrophysical plasmas, playing a key role in energy transfer and dissipation. The solar corona is thought to be heated to temperatures exceeding 10 6 K in part by turbulent processes. Using the highest-resolution white-light total solar eclipse image obtained during the 2017 August 21 eclipse, we present quantitative constraints on anisotropic turbulent structuring in the solar corona below a heliocentric distance of 1.4 R ⊙ . We compute power spectra in ∼0.4 R ⊙ wide square subregions extending outward from the solar surface, separating observed structures into three magnetic categories: closed-field, open-field, and mixed magnetic field regions. Spectral slopes are measured separately along directions parallel and perpendicular to the principal axes of the observed anisotropy in k -space. Comparing closed- to open-field regions, we observe a systematic steepening in the k ⊥ spectra, a comparatively consistent k ∥ spectra, and an increase in anisotropy with decreasing complexity in magnetic topology. These results are consistent with a quasi-2D plus slab organization of coronal fluctuations, in which the k ⊥ spectra primarily reflect quasi-two-dimensional structuring, while the k ∥ spectra are dominated by field-aligned, slab-like fluctuations. The comparison of these spectra across different magnetic topologies provides evidence for developing anisotropic turbulence within 0.4 R ⊙ of the solar surface.