The chromosphere above a $\delta$-sunspot in the presence of fan-shaped jets

Abstract

$\delta$-sunspots are known to be favourable locations for fast and energetic events like flares and CMEs. The photosphere of this type of sunspots has been thoroughly investigated in the past three decades. The atmospheric conditions in the chromosphere are not so well known, however. his study is focused on the chromosphere of a $\delta$-sunspot that harbours a series of fan-shaped jets in its penumbra . The aim of this study is to establish the magnetic field topology and the temperature distribution in the presence of jets in the photosphere and the chromosphere. We use data from the Swedish 1-m Solar Telescope (SST) and the Solar Dynamics Observatory. We invert the spectropolarimetric FeI 6302~Å and CaII ~8542~Å data from the SST using the the non-LTE inversion code NICOLE to estimate the magnetic field configuration, temperature and velocity structure in the chromosphere. A loop-like magnetic structure is observed to emerge in the penumbra of the sunspot. The jets are launched from the loop-like structure. Magnetic reconnection between this emerging field and the pre-existing vertical field is suggested by hot plasma patches on the interface between the two fields. The height at which the reconnection takes place is located between $\log {\tau }_{500}=-2$ and $\log {\tau }_{500}=-3$. The magnetic field vector and the atmospheric temperature maps show a stationary configuration during the whole observation.

12 pages, 15 figures. Recommended for publication in A&A

References in corpus (9)

• CRISP Spectropolarimetric Imaging of Penumbral Fine Structure
• CRISPRED: A data pipeline for the CRISP imaging spectropolarimeter
• Jets in coronal holes: Hinode observations and 3D computer modelling
• An Open Source, Massively Parallel Code for Non-LTE Synthesis and Inversion of Spectral Lines and Zeeman-induced Stokes Profiles
• $\delta$-Sunspot Formation in Simulation of Active-Region-Scale Flux Emergence
• H-alpha features with hot onsets III. Fibrils in Lyman-alpha and with ALMA
• Formal Solutions for Polarized Radiative Transfer. I. The DELO Family
• Enhancement of a sunspot light wall with external disturbances
• Fan-shaped jets in three dimensional reconnection simulation as a model of ubiquitous solar jets

Cited by in corpus (4)

• The Solar Orbiter mission -- Science overview
• Flare-productive active regions
• Height dependence of the penumbral fine-scale structure in the inner solar atmosphere
• Can Injection Model Replenish the Filaments in Weak Magnetic Environment?