Prominence fine structures in weakly twisted and highly twisted magnetic flux ropes

TL;DR

This study uses simulations to identify observable differences in prominences supported by weakly versus strongly twisted magnetic flux ropes, aiding in magnetic structure diagnostics.

Contribution

It demonstrates that prominences exhibit distinct features depending on flux rope twist, providing a new method to distinguish magnetic configurations observationally.

Findings

Weakly-twisted flux ropes produce transient, high-speed threads with evident horns.

Highly-twisted flux ropes feature stable, longer, and magnetically connected threads.

Prominence morphology varies significantly with flux rope twist, especially in the prominence spine deviation.

Abstract

Many prominences are supported by magnetic flux ropes. One important question is how we can determine whether the flux rope is weakly-twisted or strongly-twisted. In this paper, we attempted to check whether prominences supported by weakly-twisted and strongly-twisted flux ropes can manifest different features so that we might distinguish the two types of magnetic structures by their appearance. We performed pseudo three-dimensional simulations of two magnetic flux ropes with different twists. We found that the resulting two prominences differ in many aspects. The prominence supported by a weakly-twisted flux rope is composed mainly of transient threads, forming high-speed flows inside the prominence. Its horns are evident. Conversely, the one supported by a highly-twisted flux rope consists mainly of stable quasi-stationary threads, including longer independently trapped threads and shorter magnetically connected threads. It is also revealed that the prominence spine deviates from the flux rope axis in the vertical direction and from the photospheric polarity inversion line projected on the solar surface, especially for the weakly-twisted magnetic flux rope. The two types of prominences differ significantly in appearance. It is also suggested that a piling-up of short threads in highly-twisted flux ropes might account for the vertical-like threads in some prominences.