2023/10/11 by V. M. Uritsky, J. A. Klimchuk, Uritsky, Vadim M. +1 · 2 citations
Physics and Astronomy · #Data Analysis #FOS: Physical sciences #Instrumentation and Methods for Astrophysics (astro-ph.IM) #Plasma Physics (physics.plasm-ph) #Solar and Space Plasma Dynamics #Solar and Stellar Astrophysics (astro-ph.SR) #Statistics and Probability (physics.data-an) #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.2310.07102
openalex publication_date 2023/10/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report results of an in-depth numerical investigation of three-dimensional projection effects which could influence the observed loop-like structures in an optically thin solar corona. Several archetypal emitting geometries are tested, including collections of luminous structures with circular cross-sections of fixed and random size, light-emitting structures with highly anisotropic cross-sections, as well as two-dimensional stochastic current density structures generated by fully-developed magnetohydrodynamic (MHD) turbulence. A comprehensive set of statistical signatures is used to compare the line of sight -integrated emission signals predicted by the constructed numerical models with the loop profiles observed by the extreme ultraviolet telescope onboard the flight 2.1 of the High-Resolution Coronal Imager (Hi-C). The results suggest that typical cross-sectional emission envelopes of the Hi-C loops are unlikely to have high eccentricity, and that the observed loops cannot be attributed to randomly oriented quasi-two dimensional emitting structures, some of which would produce anomalously strong optical signatures due to an accidental line-of-sight alignment expected in the coronal veil scenario \citepmalanushenko2022. The possibility of apparent loop-like projections of very small (close to the resolution limit) or very large (comparable with the size of an active region) light-emitting sheets remains open, but the intermediate range of scales commonly associated with observed loop systems is most likely filled with true quasi-one dimensional (roughly axisymmetric) structures embedded into the three-dimensional coronal volume.