Observations of the Formation and Disappearance of a Funnel Prominence

TL;DR

This observational study details the dynamic formation and disappearance processes of a funnel prominence, highlighting the roles of coronal loop evolution, plasma flows, and magnetic reconnection in prominence lifecycle.

Contribution

It provides new insights into the formation and disappearance mechanisms of funnel prominences through detailed observational analysis.

Findings

Cool plasma flows along coronal loops contribute to prominence formation.

Magnetic reconnection may drive vertical downflows leading to prominence disappearance.

U-shaped coronal loops and coronal cavity dynamics are key to prominence evolution.

Abstract

We present an observational study of the formation and disappearance of a funnel prominence. Before the funnel prominence formed, cool materials from the top of a preexisting polar crown prominence flowed along saddle-shaped coronal loops to their base, forming a smaller prominence. Meanwhile, the saddle-shaped coronal loops gradually rose, and U-shaped coronal loops, termed prominence horns, began to appear along with a coronal cavity. Afterwards, a cool column emerged from the chromosphere, rose vertically into the corona, and then moved laterally to be transported into the U-shaped coronal loops. The formed prominence slid into the chromosphere, while the U-shaped coronal loops and the coronal cavity became more pronounced. As cool materials accumulated at the base of the U-shaped coronal loops, these loops underwent a significant descent and a V-shaped structure appeared at the base of the cool materials, indicating that the U-shaped coronal loops may be dragged down to sag. Subsequently, cool materials from the V-shaped structure continued to flow almost vertically toward the chromosphere, forming the funnel prominence. The vertical downflows might be produced by magnetic reconnection within or between the sagging field lines. Due to persistent vertical downflows, the U-shaped coronal loops were lifted up and prominence materials followed along inclined coronal loops towards the chromosphere, causing the funnel prominence to disappear. Our observations suggest that chromospheric plasma transported into a coronal cavity and then drained out via vertical downflows can form a funnel prominence.