Fine-scale Structures of Flux Ropes Tracked by Erupting Material

TL;DR

This study uses Solar Dynamics Observatory data to analyze the fine-scale structures of flux ropes associated with eruptions, revealing their composition, footpoints, and magnetic fluxes, and providing insights into their formation and evolution.

Contribution

It provides detailed observations of flux rope fine structures, their footpoints, and magnetic properties, advancing understanding of flux rope composition and magnetic connectivity.

Findings

Flux ropes consist of 85-102 fine-scale structures with ~1.6 arcsec width.

Flux rope footpoints are rooted in opposite polarity magnetic fields with specific flux ranges.

Almost half of the footpoints show converging magnetic motions before flux rope appearance.

Abstract

We present the Solar Dynamics Observatory observations of two flux ropes respectively tracked out by material from a surge and a failed filament eruption on 2012 July 29 and August 04. For the first event, the interaction between the erupting surge and a loop-shaped filament in the east seems to "peel off" the filament and add bright mass into the flux rope body. The second event is associated with a C-class flare that occurs several minutes before the filament activation. The two flux ropes are respectively composed of 85$\pm$12 and 102$\pm$15 fine-scale structures, with an average width of about 1$\arcsec$.6. Our observations show that two extreme ends of the flux rope are rooted in the opposite polarity fields and each end is composed of multiple footpoints (FPs) of the fine-scale structures. The FPs of the fine-scale structures are located at network magnetic fields, with magnetic fluxes from 5.6$\times10^{18}$ Mx to 8.6$\times10^{19}$ Mx. Moreover, almost half of the FPs show converging motion of smaller magnetic structures over 10 hr before the appearance of the flux rope. By calculating the magnetic fields of the FPs, we deduce that the two flux ropes occupy at least 4.3$\times10^{20}$ Mx and 7.6$\times10^{20}$ Mx magnetic fluxes, respectively.