Erupting filaments with large enclosing flux tubes as sources of high-mass 3-part CMEs, and erupting filaments in the absence of enclosing flux tubes as sources of low-mass unstructured CMEs

TL;DR

This study investigates the relationship between filament eruption structures and CME morphology, revealing that large flux tubes produce structured 3-part CMEs, while smaller flux tubes lead to unstructured CMEs, with significant differences in mass distribution.

Contribution

It establishes a detailed link between filament system structure and CME morphology, differentiating the origins of structured and unstructured CMEs based on flux tube size.

Findings

3-part CMEs often originate from large flux tubes with pre-existing loop structures.

Unstructured CMEs have narrower mass distribution but similar total mass compared to structured CMEs.

Erupting filaments without large enclosing flux tubes produce unstructured, low-mass CMEs.

Abstract

The 3-part appearance of many CMEs arising from erupting filaments emerges from a large magnetic flux tube structure, consistent with the form of the erupting filament system. Other CMEs arising from erupting filaments lack a clear 3-part structure and reasons for this have not been researched in detail. This paper aims to further establish the link between CME structure and the structure of the erupting filament system and to investigate whether CMEs which lack a 3-part structure have different eruption characteristics. A survey is made of 221 near-limb filament eruptions observed from 2013/05/03-2014/06/30 by EUV imagers and coronagraphs. 92 filament eruptions are associated with 3-part structured CMEs, 41 eruptions are associated with unstructured CMEs. The remaining 88 are categorized as failed eruptions. For 34% of the 3-part CMEs, processing applied to EUV images reveals the erupting front edge is a pre-existing loop structure surrounding the filament, which subsequently erupts with the filament to form the leading bright front edge of the CME. This connection is confirmed by a flux-rope density model. Furthermore, the unstructured CMEs have a narrower distribution of mass compared to structured CMEs, with total mass comparable to the mass of 3-part CME cores. This study supports the interpretation of 3-part CME leading fronts as the outer boundaries of a large pre-existing flux tube. Unstructured (non 3-part) CMEs are a different family to structured CMEs, arising from the eruption of filaments which are compact flux tubes in the absence of a large system of enclosing closed field.