High cadence observations of a global coronal wave by EUVI/STEREO

TL;DR

This study utilizes high-cadence EUVI/STEREO observations to analyze a large-scale coronal wave associated with a weak flare and CME, revealing wave deceleration indicative of a freely propagating MHD wave.

Contribution

First high-cadence EUVI observations provide detailed insights into the dynamics and initiation mechanisms of coronal waves linked to CMEs.

Findings

Coronal wave shows deceleration, consistent with a freely propagating MHD wave.

Wave initiation likely driven by CME expanding flanks, not the weak flare.

Wave propagates over a limited distance before decelerating.

Abstract

We report a large-scale coronal wave (so-called "EIT wave") observed with high cadence by EUVI onboard STEREO in association with the GOES B9.5 flare and double CME event on 19 May 2007. The EUVI instruments provide us with the unprecedented opportunity to study the {\it dynamics} of flare/CME associated coronal waves imaged in the extreme ultraviolet. The coronal wave under study reveals deceleration, indicative of a freely propagating MHD wave. Complementary analysis of the associated flare and erupting filament/CME hint at wave initiation by the CME expanding flanks, which drive the wave only over a limited distance. The associated flare is very weak and occurs too late to account for the wave initiation.