A Full Study on the Sun-Earth Connection of an Earth-Directed CME Magnetic Flux Rope

TL;DR

This study investigates the initiation, evolution, and Earth-impact of a specific CME magnetic flux rope event using multi-spacecraft observations, modeling, and reconstruction techniques to understand its structure and propagation.

Contribution

It provides a comprehensive analysis of the CME's magnetic flux rope formation, eruption mechanisms, 3D structure, and propagation modeling, integrating multiple observational and reconstruction methods.

Findings

The MFR was initiated by kink and torus instabilities.

The CME's 3D structure was well-fitted by the GCS model.

Propagation modeling aligned with in-situ measurements.

Abstract

We present an investigation of an eruption event of coronal mass ejection (CME) magnetic flux rope (MFR) from source active region (AR) NOAA 11719 on 11 April 2013 utilizing observations from SDO, STEREO, SOHO, and WIND spacecraft. The source AR consists of pre-existing sigmoidal structure stacked over a filament channel which is regarded as MFR system. EUV observations of low corona suggest a further development of this MFR system by added axial flux through tether-cutting reconnection of loops at the middle of sigmoid under the influence of continuous slow flux motions during past two days. Our study implies that the MFR system in the AR is initiated to upward motion by kink-instability and further driven by torus-instability. The CME morphology, captured in simultaneous three-point coronagraph observations, is fitted with Graduated Cylindrical Shell (GCS) model and discerns an MFR topology with orientation aligning with magnetic neutral line in the source AR. This MFR expands self-similarly and is found to have source AR twist signatures in the associated near Earth magnetic cloud (MC). We further derived kinematics of this CME propagation by employing a plethora of stereoscopic as well as single spacecraft reconstruction techniques. While stereoscopic methods perform relatively poorly compared to other methods, fitting methods worked best in estimating the arrival time of the CME compared to in-situ measurements. Supplied with values of constrained solar wind velocity, drag parameter and 3D kinematics from GCS fit, we construct CME kinematics from the drag based model consistent with in-situ MC arrival.