A Chain of Winking (Oscillating) Filaments Triggered by an Invisible Extreme-Ultraviolet Wave

Abstract

Winking (oscillating) filaments have been observed for many years. However, observations of successive winking filaments in one event have not been reported yet. In this paper, we present the observations of a chain of winking filaments and a subsequent jet that are observed right after the X2.1 flare in AR11283. The event also produced an Extreme-ultraviolet (EUV) wave that has two components: upward dome-like wave (850 km s −1 ) and lateral surface wave (554 km s −1 ) which was very weak (or invisible) in imaging observations. By analyzing the temporal and spatial relationships between the oscillating filaments and the EUV waves, we propose that all the winking filaments and the jet were triggered by the weak (or invisible) lateral surface EUV wave. The oscillation of the filaments last for two or three cycles, and their periods, Doppler velocity amplitudes, and damping times are 11 -22 minutes, 6 -14 km s −1 , and 25 -60 minutes, respectively. We further estimate the radial component magnetic field and the maximum kinetic energy of the filaments, and they are 5 -10 Gauss and ∼ 10 19 J, respectively. The estimated maximum kinetic energy is comparable to the minimum energy of ordinary EUV waves, suggesting that EUV waves can efficiently launch filament oscillations on their path. Based on our analysis results, we conclude that the EUV wave is a good agent for triggering and connecting successive but separated solar activities in the solar atmosphere, and it is also important for producing solar sympathetic eruptions.

On a Small-scale EUV Wave: The Driving Mechanism and the Associated Oscillating Filament

“…With coronal EUV observations, it is found that energetic large-scale coronal EUV wave can also trigger filament oscillations (e.g., Eto et al 2002;Okamoto et al 2004;. Recently, Shen et al (2014a) found that a chain of oscillating filaments are caused by a very weak EUV wave that was associated with an energetic GOES X2.1 flare. The authors also proposed that the interaction angle between the incoming EUV wave and the filament main axis is important to trigger what types of filament oscillation.…”

“…Therefore, many earlier studies also believe that the driver of EUV waves are the associated flares (e.g., Warmuth et al 2004a,b;Cliver et al 2005). However, along with the development of advanced solar telescopes, more and more studies based on high resolution observations indicate that global EUV waves are in fact excited by the associated CMEs (e.g., Chen et al 2006;Chen & Wu 2011;Ma, et al 2009;Ma et al 2010;Cheng et al 2012;Shen & Liu 2012a,b;Shen et al 2013aShen et al , 2014aMuhr et al 2014;Zhou & Liang 2017).…”

“…In most cases, only one bright wavefront can be detected. However, sometimes there are two simultaneous bright wavefront can be observed in a single eruption, in which one is fast and it can be detected in a large distance range, while the other is slow and its speed is about one third of the preceding fast one (Delannée & Aulanier 1999;Delannée 2000;Chen & Wu 2011;Shen et al 2014a;Kumar et al 2013;Guo et al 2015). Chen et al (2016) recently found that part of a fast propagating wavefront can convert to a slowmode wave, which is trapped inside magnetic loops and manifested as a stationary wave front.…”

Large-scale Globally Propagating Coronal Waves

“…Okamoto et al (2004) found that 11 out of 14 EIT wave events with simultaneous Hα coverage did excite filament oscillations. Recently, Shen et al (2014) observed a chain of successive winking filaments. The AIA wave that triggered these oscillations was very weak, which confirms the earlier finding that filaments are particularly sensitive tracers of coronal waves.…”

Gradual Magnetic Evolution of Sunspot Structure and Filament–corona Dynamics Associated With the X1.8 Flare in Ar11283

“…As mentioned, it released two X-class flares on September 6 and 7, respectively. The eruption processes of both events have been well studied by many authors (Wang et al 2012;Feng et al 2013;Jiang & Feng 2013;Zharkov et al 2013;Liu et al 2014;Ruan et al 2014;Shen et al 2014). Thus, the details of the overall evolution of this AR will not be repeated here.…”