Observations of a peculiar coronal wave inside a pseudo-streamer structure

Abstract

Coronal extreme ultraviolet (EUV) waves are large-scale disturbances propagating in the corona and are closely associated with solar eruptions. They can disturb the ambient plasma over a wide temperature range, resulting in simultaneous observations in multiple EUV passbands, and the wavefronts are typically best observed in AIA 193 and 211 Å channels with temperatures ranging from 1.6 to 2 MK. Here, we report a peculiar EUV wave that was invisible in the 193 and 211 Å but appeared instead in AIA 171 Å, corresponding to a lower temperature. Driven by a coronal jet, the wave propagated at a speed of ∼560 km s⁻¹. The differential emission measure (DEM) analysis shows that the emission of the wavefront concentrated at ∼1.25 MK, lower than the typical predominant temperatures. In addition, the fields extrapolated using the potential field source surface (PFSS) method indicate the existence of a typical pseudo-streamer structure. Hence, we propose that it is possibly the first case of an EUV wave occurring and propagating inside a pseudo-streamer, and its visibility is likely determined by the relatively cooler plasma within the pseudo-streamer.