Stereoscopic diagnosing of a filament-cavity flux rope system by tracing the path of a two-sided-loop jet

TL;DR

This study uses stereoscopic solar observations to analyze the magnetic structure and formation mechanisms of a filament-cavity flux rope system, revealing the role of magnetic reconnection and quantifying the magnetic twist.

Contribution

It provides new insights into the fine magnetic structure of filament-cavity systems and confirms theoretical flux rope models through observational evidence.

Findings

Magnetic reconnection triggers the two-sided-loop jet.

The magnetic twist in the filament is at least 5π.

The magnetic structure aligns with flux rope models.

Abstract

The fine magnetic structure is vitally important to understanding the formation, stabilization and eruption of solar filaments, but so far, it is still an open question yet to be resolved. Using stereoscopic observations taken by the Solar Dynamics Observatory and Solar TErrestrial RElations Obsevatory, we studied the generation mechanism of a two-sided-loop jet (TJ) and the ejection process of the jet plasma into the overlying filament-cavity system. We find that the generation of the two-sided-loop jet was due to the magnetic reconnection between an emerging flux loop and the overlying filament. The jet's two arms ejected along the filament axis during the initial stage. Then, the north arm bifurcated into two parts at about 50 Mm from the reconnection site. After the bifurcation, the two bifurcated parts were along the filament axis and the cavity which hosted the filament, respectively. By tracing the ejecting plasma flows of the TJ inside the filament, we not only measured that the magnetic twist stored in the filament was at least 5$\pi$ but also found that the fine magnetic structure of the filament-cavity flux rope system is in well agreement with the theoretical results of Magnetic flux rope models.