Spatially Resolved Signatures of Bidirectional Flows Observed in Inverted-Y Shaped Jets

C J Nelson,S Bennett,N Freij,R Erdélyi,M Mathioudakis

doi:10.3847/1538-4357/ab3a54

Abstract

Abstract Numerous apparent signatures of magnetic reconnection have been reported in the solar photosphere, including inverted-Y shaped jets. The reconnection at these sites is expected to cause localized bidirectional flows and extended shock waves; however, these signatures are rarely observed as extremely high spatial-resolution data are required. Here, we use Hα imaging data sampled by the Swedish Solar Telescope’s CRisp Imaging SpectroPolarimeter to investigate whether bidirectional flows can be detected within inverted-Y shaped jets near the solar limb. These jets are apparent in the Hα line wings, while no signature of either jet is observed in the Hα line core, implying reconnection took place below the chromospheric canopy. Asymmetries in the Hα line profiles along the legs of the jets indicate the presence of bidirectional flows, consistent with cartoon models of reconnection in chromospheric anemone jets. These asymmetries are present for over two minutes, longer than the lifetimes of Rapid Blue Excursions, and beyond ±1 Å into the wings of the line indicating that flows within the inverted-Y shaped jets are responsible for the imbalance in the profiles, rather than motions in the foreground. Additionally, surges form following the occurrence of the inverted-Y shaped jets. This surge formation is consistent with models, which suggests such events could be caused by the propagation of shock waves from reconnection sites in the photosphere to the upper atmosphere. Overall, our results provide evidence that magnetic reconnection in the photosphere can cause bidirectional flows within inverted-Y shaped jets and could be the driver of surges.

Highlights

A huge range of potential signatures of magnetic reconnection in the solar photosphere have been reported in the literature
Cartoon models presented in the literature suggest that bidirectional reconnection outflows should exist in one footpoint of the inverted-Y shaped jets; hints that such bidirectional flows exist have only rarely been reported to date as wide-band imaging data have typically been used to study these events
It should be noted that a careful alignment between the Solar Dynamics Observatory’s Atmospheric Imaging Assembly (SDO/AIA) data and the CRISP data was completed to confirm that the ejections observed in the EUV channels corresponded to those detected in the ground-based data, the analysis presented here was conducted on the nonrotated data in order to limit errors induced by interpolating the images

Summary

Introduction

A huge range of potential signatures of magnetic reconnection in the solar photosphere have been reported in the literature. Similar events have been identified at the footpoints of coronal loops (Chitta et al 2017) and in sunspot light-bridges (Tian et al 2018) indicating that inverted-Y shaped jets and, magnetic reconnection may be prevalent throughout the solar photosphere. It is, important that further analysis of these events is conducted using high spatial and temporal resolution data in order to better understand their formation and evolution.

Results

Discussion

Conclusion