Magnetic flux ropes are highly twisted, current-carrying magnetic fields. They are crucial for the instability of plasma involved in solar eruptions, which may lead to adverse space weather effects. Here we present observations of a flaring using the highest resolution chromospheric images from the 1.6-m New Solar Telescope at Big Bear Solar Observatory, supplemented by a magnetic field extrapolation model. A set of loops initially appear to peel off from an overall inverse S-shaped flux bundle, and then develop into a multi-stranded twisted flux rope, producing a two-ribbon flare. We show evidence that the flux rope is embedded in sheared arcades and becomes unstable following the enhancement of its twists. The subsequent motion of the flux rope is confined due to the strong strapping effect of the overlying field. These results provide a first opportunity to witness the detailed structure and evolution of flux ropes in the low solar atmosphere.
1.New Jersey Inst Technol, Space Weather Res Lab, Newark, NJ 07102 USA 2.New Jersey Inst Technol, Big Bear Solar Observ, Big Bear City, CA 92314 USA 3.Univ Sci & Technol China, CAS Key Lab Geospace Environm, Dept Geophys & Planetary Sci, Hefei 230026, Peoples R China 4.Collaborat Innovat Ctr Astronaut Sci & Technol, Beijing, Peoples R China 5.Seoul Natl Univ, Astron Program, Dept Phys & Astron, Seoul 151747, South Korea 6.Chinese Acad Sci, Purple Mt Observ, Nanjing 210008, Jiangsu, Peoples R China
