An in-depth analysis of quiet-Sun IRIS Brightenings

Abstract

Small-scale brightenigs are ubiquitous, dynamic and energetic phenomena found in the chromopshere. An advanced filter-detection algorithm applied to high-resolution observations from the Interface Region Imaging Spectrograph enables the detection of these brightenings close to the noise level. This algorithm also tracks the movement of these brightenings and extracts their characteristics. This work outlines the results of an in-depth analysis of a quiet-Sun dataset including a comparison of a brighter domain - associated with a super-granular boundary - to the quiescent inter-network domains. Several characteristics of brightenings from both domains are extracted and analysed, providing a range of sizes, durations, brightness values, travel distances, and speeds. The ``Active" quiet-Sun events tend to travel shorter distances and at slower speeds along the plane-of-sky than their ``True" quiet-Sun counterparts. These results are consistent with the magnetic field model of super-granular photospheric structures and the magnetic canopy model of the chromosphere above. Spectroscopic analyses reveal that BPs demonstrate blue-shift (as well as some bi-directionality) and that they may rise from the chromosphere into the TR. We believe these bright points to be magnetic in nature, are likely the result of magnetic reconnection, and follow current sheets between magnetic field gradients, rather than along magnetic field lines themselves.

18 pages, 11 figures

References in corpus (19)

• The Interface Region Imaging Spectrograph (IRIS)
• The Solar Orbiter mission -- Science overview
• Hot Explosions in the Cool Atmosphere of the Sun
• RHESSI Microflare Statistics II. X-ray Imaging, Spectroscopy & Energy Distributions
• Evidence of Non-Thermal Particles in Coronal Loops Heated Impulsively by Nanoflares
• Microflares and the Statistics of X-ray Flares
• Solar ultraviolet bursts
• Frequently Occurring Reconnection Jets from Sunspot Light Bridges
• Microflare Heating of a Solar Active Region Observed with NuSTAR, Hinode/XRT, and SDO/AIA
• The formation of IRIS diagnostics V. A quintessential model atom of C II and general formation properties of the C II lines at 133.5 nm
• Accelerated electrons observed down to <7 keV in a NuSTAR solar microflare
• The formation of IRIS diagnostics VI. The Diagnostic Potential of the C II Lines at 133.5 nm in the Solar Atmosphere
• IRIS observations of short-term variability in moss associated with transient hot coronal loops
• The Formation of IRIS Diagnostics. VII. The Formation of the OI 135.56 nm Line in the Solar Atmosphere
• Are Chromospheric Nanoflares a Primary Source of Coronal Plasma?
• NuSTAR hard X-ray observation of a sub-A class solar flare
• Large-amplitude quasi-periodic pulsations as evidence of impulsive heating in hot transient loop systems detected in the EUV with SDO/AIA
• NuSTAR observations of a repeatedly microflaring active region
• NuSTAR Observation of a Minuscule Microflare in a Solar Active Region