Observations of the Coronal Mass Ejection with a Complex Acceleration Profile

TL;DR

This study analyzes a complex coronal mass ejection (CME) event with multiple acceleration phases, revealing that various mechanisms like kink instability, flare reconnection, and CME-CME collision contribute to its evolution.

Contribution

It provides detailed observations of a CME with a complex acceleration profile using TESIS EUV imaging, highlighting multiple acceleration mechanisms involved in CME dynamics.

Findings

CME had three distinct acceleration phases with different causes.

Kink instability triggered the CME onset.

CME-CME collision influenced the deceleration and secondary acceleration.

Abstract

We study the coronal mass ejection (CME) with a complex acceleration profile. The event occurred on April 23, 2009. It had an impulsive acceleration phase, an impulsive deceleration phase, and a second impulsive acceleration phase. During its evolution, the CME showed signatures of different acceleration mechanisms: kink instability, prominence drainage, flare reconnection, and a CME-CME collision. The special feature of the observations is the usage of the TESIS EUV telescope. The instrument could image the solar corona in the Fe 171 \AA\ line up to a distance of 2 $R_\odot$ from the center of the Sun. This allows us to trace the CME up to the LASCO/C2 field of view without losing the CME from sight. The onset of the CME was caused by kink instability. The mass drainage occurred after the kink instability. The mass drainage played only an auxiliary role: it decreased the CME mass, which helped to accelerate the CME. The first impulsive acceleration phase was caused by the flare reconnection. We observed the two ribbon flare and an increase of the soft X-ray flux during the first impulsive acceleration phase. The impulsive deceleration and the second impulsive acceleration phases were caused by the CME-CME collision. The studied event shows that CMEs are complex phenomena that cannot be explained with only one acceleration mechanism. We should seek a combination of different mechanisms that accelerate CMEs at different stages of their evolution.