Homologous Flux Ropes Observed by SDO/AIA

TL;DR

This study reports observations of four homologous flux ropes in an active solar region, highlighting their formation, evolution, and eruption behaviors, and providing insights into flux rope dynamics and their role in coronal mass ejections.

Contribution

First detailed observation of multiple homologous flux ropes in a single active region, revealing their formation, evolution, and eruption characteristics with implications for CME prediction.

Findings

Multiple flux ropes form successively at the same location.

Slow-rise flux ropes may not lead to CMEs.

Fast-eruption flux ropes are associated with CMEs.

Abstract

We firstly present the Solar Dynamics Observatory observations of four homologous flux ropes in active region (AR) 11745 on 2013 May 20-22. The four flux ropes are all above the neutral line of the AR, with endpoints anchoring at the same region, and have the generally similar morphology. For the first three flux ropes, they rose up with a velocity of less than 30 km s$^{-1}$ after their appearances, and subsequently their intensities at 131 {\AA} decreased and the flux ropes became obscure. The fourth flux rope erupted ultimately with a speed of about 130 km s$^{-1}$ and formed a coronal mass ejection. The associated filament showed an obvious anti-clockwise twist motion at the initial stage, and the twist was estimated at 4$\pi$. This indicates that kink instability possibly triggers the early rise of the fourth flux rope. The activated filament material was spatially within the flux rope and they showed consistent evolution in their early stages. Our findings provide new clues for understanding the characteristics of flux ropes. Firstly, there are multiple flux ropes that are successively formed at the same location during an AR evolution process. Secondly, a slow-rise flux rope does not necessarily result in a CME, and a fast-eruption flux rope results in a CME.