Enhancement of a Sunspot Light Wall With External Disturbances

Abstract

Based on the Interface Region Imaging Spectrograph observations, we study the response of a solar sunspot light wall to external disturbances. A flare occurrence near the light wall caused material to erupt from the lower solar atmosphere into the corona. Some material falls back to the solar surface, and hits the light bridge (i.e., the base of the light wall), then sudden brightenings appear at the wall base followed by the rise of wall top, leading to an increase of the wall height. Once the brightness of the wall base fades, the height of the light wall begins to decrease. Five hours later, another nearby flare takes place, a bright channel is formed that extends from the flare towards the light bridge. Although no obvious material flow along the bright channel is found, some ejected material is conjectured to reach the light bridge. Subsequently, the wall base brightens and the wall height begins to increase again. Once more, when the brightness of the wall base decays, the wall top fluctuates to lower heights. We suggest, based on the observed cases, that the interaction of falling material and ejected flare material with the light wall results in the brightenings of wall base and causes the height of the light wall to increase. Our results reveal that the light wall can be not only powered by the linkage of p-mode from below the photosphere, but may also be enhanced by external disturbances, such as falling material.

The chromosphere above a δ-sunspot in the presence of fan-shaped jets

“…Chromospheric fan-shaped jets launched from sunspots have been reported by several authors (Roy 1973;Asai et al 2001;Shimizu et al 2009;Hou et al 2016;Robustini et al 2016;Li et al 2016;Yang et al 2016). From these previous observations, we know that the length of these jets is of tens of Mm.…”

Penumbral Waves Driving Solar Fan-shaped Chromospheric Jets

“…On-disk fan-shaped jets appear dark in the wings of the Hα line, while appearing bright in the line cores. They also appear as brightenings in the Ca II H (Shimizu et al 2009) and Ca II 8542 Å lines (Robustini et al 2017), while the fronts appear bright in the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA, Lemen et al 2012) , 304 Å and 171 Å channels (Robustini et al 2016), and the Interface Region Imaging Spectrograph (IRIS, De Pontieu et al 2014) 1330 Å channel (Yang et al 2016;Tian et al 2018).…”

Signatures of the impact of flare-ejected plasma on the photosphere of a sunspot light bridge

“…Only a few works (e.g., Yang et al 2016) have previously reported this kind of structure, while a light wall (above a sunspot light-bridge) has been found to form a coupled system with a flare loop (Hou et al 2016). Our analysis of AIA filtergrams and LOS magnetograms is not enough to understand the relation between the flare and the light bridge.…”

“…In case of low energy flares, plasmoids can be confined within active region loops. Zacharias et al (2011) investigated the ejection and travel of a trapped plasma blob using numerial simulations, while Yang et al (2016) analyzed the brightenings and height changes in a light wall (rooted in a light bridge) produced by the action of falling material ejected from a nearby flare. Recently, Nisticò et al (2017) evaluated the impact of confined plasma blobs on magnetodydrodynamic waves studied in coronal seismology.…”