Occurrence and Statistics of IRIS Bursts

Abstract

Small reconnection events in the lower solar atmosphere can lead to its heating, but whether such heating can propagate into higher atmospheric layers and potentially contribute to coronal heating is an open question. We carry out a large statistical analysis of all IRIS observations from 2013 and 2014. We identified "IRIS burst" (IB) spectra via a k-means analysis by classifying and selecting Si IV spectra with superimposed blend lines on top of bursts, which indicate low atmospheric heating. We found that ~8% of all observations show IBs with about 0.01% of all recorded IRIS spectra being IB spectra. We found varying blend absorption levels, which may indicate different depths of the reconnection event and heating. IBs are statistically visible with similar properties and timings in the spectral lines Mg II, C II, and Si IV, but invisible in Fe XXI. By statistically analyzing co-spatial AIA lightcurves, we found systematic enhancements in AIA 1600 and AIA 1700, but no clear response to bursts in all other AIA wavelengths (94, 131, 171, 193, 211, 304, 335) in a timeframe of $\pm 6$ minutes around the burst. This may indicate that heating due to IBs is confined within the lower atmosphere and dissipates before reaching temperatures or formation heights covered by the hotter AIA lines. Our developed methods are applicable for statistical analyses of any co-observed data sets and allow us to efficiently analyze millions of spectra and lightcurves simultaneously.

accepted for publication by A&A

References in corpus (11)

• Hot Explosions in the Cool Atmosphere of the Sun
• The 2014 March 29 X-flare: sub-arcsecond resolution observations of Fe XXI 1354.1
• Intermittent reconnection and plasmoids in UV bursts in the low solar atmosphere
• Ellerman bombs and UV bursts: transient events in chromospheric current sheets
• Detection of supersonic downflows and associated heating events in the transition region above sunspots
• Explosive events in active region observed by IRIS and SST/CRISP
• Solar Ellerman Bombs in 1-D Radiative Hydrodynamics
• RADYN simulations of non-thermal and thermal models of Ellerman bombs
• Exploring mutual information between IRIS spectral lines. I. Correlations between spectral lines during solar flares and within the quiet Sun
• Exploring mutual information between IRIS spectral lines. II. Calculating the most probable response in all spectral windows
• Revisiting the Spectral Features of Ellerman Bombs and UV Bursts. I. Radiative Hydrodynamic Simulations

Cited by in corpus (12)

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• Spatial distributions of EUV brightenings in the quiet-Sun
• Small-scale magnetic flux emergence preceding a chain of energetic solar atmospheric events
• Shape-based clustering of synthetic Stokes profiles using k-means and k-Shape
• Magnetic Topology of quiet-Sun Ellerman bombs and associated Ultraviolet brightenings
• Small-scale dynamic phenomena associated with interacting fan-spine topologies: quiet-Sun Ellerman bombs, UV brightenings, and chromospheric inverted-Y-shaped jets
• Explosive Events in the Quiet Sun Near and Beyond the Solar Limb Observed with the Interface Region Imaging Spectrograph (IRIS)
• Quiet Sun Ellerman bombs as a possible proxy for reconnection-driven spicules
• Automatic detection of Ellerman bombs using Deep Learning
• Searching for signatures of H $\alpha$ spicule-like features in the solar transition region
• Investigating datasets with high IRIS burst prevalence
• IRIS burst properties in active regions