Cusp-shaped structure of a jet observed by IRIS and SDO

TL;DR

This study provides detailed observations of a cusp-shaped solar jet, revealing how magnetic reconnection influences its structure and evolution, enhancing understanding of jet formation and dynamics.

Contribution

It offers the first detailed IRIS and SDO observations of a cusp-shaped jet, illustrating the role of magnetic reconnection in its formation and evolution.

Findings

Mini-prominences collide with loop-like system triggering the jet.

Brightening blobs in the spire move upward with rotation.

Bidirectional flows lead to the jet’s disappearance.

Abstract

On 29 August 2014, the trigger and evolution of a cusp-shaped jet were captured in detail at 1330 {\AA} by the Interface Region Imaging Spectrograph.At first, two neighboring mini-prominences arose in turn from low solar atmosphere and collided with a loop-like system over them. The collisions between the loop-like system and the mini-prominences lead to the blowout and then a cusp-shaped jet formed with a spire and an arch-base. In the spire, many brightening blobs originating from the junction between the spire and the arch-base, moved upward in a rotating manner and then in a straight line in the late phase of the jet. In the arch-base, dark and bright material simultaneously tracked in a fan-like structure and the majority of the material moved along the fan's threads. At the later phase of the jet's evolution, bidirectional flows emptied the arch-base, while down-flows emptied the spire, thus making the jet entirely vanish. The extremely detailed observations in this study shed new light on how magnetic reconnection alters the inner topological structure of a jet, and provide a beneficial complement for understanding current jet models.