Sequential Lid Removal in a Triple-Decker Chain of CME-Producing Solar Eruptions

TL;DR

This study examines a sequence of three solar eruptions from a bipolar active region with a triple-decker flux rope structure, revealing how successive eruptions trigger each other through lid removal mechanisms.

Contribution

It provides detailed observational evidence of sequential CME eruptions from a triple-decker flux rope configuration and elucidates the triggering process via lid removal.

Findings

Three consecutive CMEs were driven by eruptions of stacked flux ropes.

Lid removal by one eruption plausibly triggers subsequent eruptions.

Flux cancellation at the PIL likely initiates the initial confined eruption.

Abstract

We investigate the onsets of three consecutive coronal mass ejection (CME) eruptions in 12 hours from a large bipolar active region (AR) observed by SDO, STEREO, RHESSI, and GOES. Evidently, the AR initially had a triple-decker configuration: three flux ropes in a vertical stack above the polarity inversion line (PIL). Upon being bumped by a confined eruption of the middle flux rope, the top flux rope erupts to make the first CME and its accompanying AR-spanning flare arcade rooted in a far-apart pair of flare ribbons. The second CME is made by eruption of the previously-arrested middle flux rope, which blows open the flare arcade of the first CME and produces a flare arcade rooted in a pair of flare ribbons closer to the PIL than those of the first CME. The third CME is made by blowout eruption of the bottom flux rope, which blows open the second flare arcade and makes its own flare arcade and pair of flare ribbons. Flux cancellation observed at the PIL likely triggers the initial confined eruption of the middle flux rope. That confined eruption evidently triggers the first CME eruption. The lid-removal mechanism instigated by the first CME eruption plausibly triggers the second CME eruption. Further lid removal by the second CME eruption plausibly triggers the final CME eruption.