Searching for signatures of H $\alpha$ spicule-like features in the solar transition region

Abstract

New instrumental and telescopes covering the optical and ultra-violet spectral regions have revealed a range of small-scale dynamic features, many which may be related. For example, the range of spicule-like features hints towards a spectrum of features and not just two types; however, direct observational evidence in terms of tracking spicules across multiple wavelengths are needed in order to provide further insight into the dynamics of the Sun's outer atmosphere. This paper uses H $\alpha$ data obtained with the CRisp Imaging SpectroPolarimeter instrument on the Swedish 1-m Solar Telescope, and in the transition region using the Interface Region Imaging Spectrograph with the SJI 1400 Å channel plus spectral data via the Si IV 1394 Å line to track spicules termed Rapid Blue-shifted Excursions (RBEs). The RBEs as seen in the H $\alpha$ blue-wing images presented here can be sub-divided into two categories; a single or multi-threaded feature. Based on the H $\alpha$ spectra, the features can be divided into events showing broadening and line core absorption, events showing broadening and line core emission, events with a pure blue shifted H $\alpha$ profile without any absorption in the red wing, broadened line profile with the absorption in the blue stronger compared to the red wing. From the RBE-like events which have a Si IV 1394 Å line profile, 78% of them show a Si IV line flux increase. Most of these features show a second broadened Si IV component which is slightly blue-shifted.

arXiv comment13 pages, 11 figures

References in corpus (25)

• The Interface Region Imaging Spectrograph (IRIS)
• CRISP Spectropolarimetric Imaging of Penumbral Fine Structure
• Solar fine-scale structures. I. Spicules and other small-scale, jet-like events at the chromospheric level: observations and physical parameters
• An Interface Region Imaging Spectrograph first view on Solar Spicules
• The solar chromosphere at high resolution with IBIS. I. New insights from the Ca II 854.2 nm line
• Search for high velocities in the disk counterpart of type II spicules
• Interplay of three kinds of motion in the disk counterpart of type II spicules: up-flow, transversal and torsional motions
• Statistical properties of the Disk Counterparts of Type II Spicules from simultaneous observations of RBEs in Ca II 8542 and Hα
• Heating signatures in the disk counterparts of solar spicules in IRIS observations
• What do iris observations of Mg II k tell us about the solar plage chromosphere?
• On the Temporal Evolution of the Disc Counterpart of Type II Spicules in Quiet Sun
• Explosive events in active region observed by IRIS and SST/CRISP
• Thermal fine structure and magnetic fields in the solar atmosphere: spicules and fibrils
• Quiet Sun Hα Transients and Corresponding Small-Scale Transition Region and Coronal Heating
• The Appearance of Spicules in High Resolution Observations of Ca II H and H-alpha
• Spicules and downflows in the solar chromosphere
• On the Active Region Bright Grains Observed in the Transition Region Imaging Channels of IRIS
• High Frequency Waves in Chromospheric Spicules
• The Effects of Spatio-temporal Resolution on Deduced Spicule Properties
• The solar chromosphere observed at 1 Hz and 0."2 resolution
• Optimization of Curvi-Linear Tracing Applied to Solar Physics and Biophysics
• High--cadence observations of spicular-type events on the Sun
• Occurrence and Statistics of IRIS Bursts
• Rapid Evolution of Type II Spicules Observed in Goode Solar Telescope On-Disk H-alpha Images
• Doppler shifts of spectral lines formed in the solar transition region and corona

Cited by in corpus (1)

• Evolution of dynamic fibrils from the cooler chromosphere to the hotter corona