An extreme-ultraviolet wave associated with the possible expansion of sheared arcades

Abstract

Context. Solar extreme-ultraviolet (EUV) waves are propagating disturbances in the corona, and they are usually accompanied with various solar eruptions, from large-scale coronal mass ejections to small-scale coronal jets. Aims. Generally, it is believed that EUV waves are driven by the rapid expansion of coronal loops overlying the erupting cores. In this paper, we present an exception of an EUV wave that was not triggered by the expansion of coronal loops overlying the erupting core. Methods. Combining the multiwavelength observations from multiple instruments, we studied the event in detail. Results. The eruption was restricted in the active region (AR) and disturbed the nearby sheared arcades (SAs) connecting the source AR to a remote AR. Interestingly, following the disturbance, an EUV wave formed close to the SAs, but far away from the eruption source. Conclusions. All the results show that the EUV wave had a closer temporal and spatial relationship with the disappearing part of SAs than the confined eruption. Hence, we suggest that the EUV wave was likely triggered by the expansion of some strands of SAs, rather than the expansion of erupting loops. It can be a possible complement for the driving mechanisms of EUV waves.

Broad and Bidirectional Narrow Quasiperiodic Fast-propagating Wave Trains Associated with a Filament-driven Halo Coronal Mass Ejection on 2023 April 21

“…It should be pointed out that the running difference images are created by forward subtracting images with a time interval of 12 s. In the running difference images, the moving wave fronts are seen as a bright arc-shaped contour followed by a black one. Unlike the loops-oscillationassociated and jet-associated wave fronts that propagated mainly limited in the front of the jet (Zhang et al 2022;Hou et al 2023) and loops (Shen et al 2018c;Sun et al 2022;Liu et al 2023), the broad QFP wave with multiple circular-shaped wave fronts (see the green arrows in Figures 2(b) and (c)) concentric with the eruption kernel propagated outward along the solar surface at about 17:48 UT. About 12 minutes later, at 18:00 UT, a series of narrow wave fronts appeared, propagated mainly in the southwest direction (Figures 2(e) and (f)).…”