Peculiar Stationary EUV Wave Fronts in the eruption on 2011 May 11

TL;DR

This study analyzes high-resolution EUV observations of a filament eruption, revealing that both slow and fast EUV waves can stop at magnetic separatrices, forming stationary fronts, which is a novel finding.

Contribution

It is the first to show that both slow and fast EUV waves can transit magnetic separatrices and form stationary fronts during a filament eruption.

Findings

Fast EUV wave propagates at ~500 km/s.

Slow EUV wave propagates at ~120 km/s.

Both waves form stationary fronts at magnetic separatrices.

Abstract

We present and interpret the observations of extreme ultraviolet (EUV) waves associated with a filament eruption on 2011 May 11.The filament eruption also produces a small B-class two ribbon flare and a coronal mass ejection (CME). The event is observed by the Solar Dynamic Observatory (SDO) with high spatio-temporal resolution data recorded by Atmospheric Imaging Assembly (AIA). As the filament erupts, we observe two types of EUV waves (slow and fast) propagating outwards. The faster EUV wave has a propagation velocity of ~ 500 km/s and the slower EUV wave has an initial velocity of ~ 120 km/s. We report for the first time that not only the slower EUV wave stops at a magnetic separatrix to form bright stationary fronts, but also the faster EUV wave transits a magnetic separatrix, leaving another stationary EUV front behind.