IRIS burst properties in active regions

Abstract

Interface Region Imaging Spectrograph (IRIS) bursts are localised features thought to be driven by magnetic reconnection. Although these events are well-studied, it remains unknown whether their properties vary as their host active regions (ARs) evolve. Here, we aim to understand whether the measurable properties of IRIS bursts are consistent during the evolution of their host ARs. We study 42 dense 400-step rasters sampled by IRIS. These rasters each covered one of seven ARs, with each AR being sampled at least four times over a minimum of 48 hours. An automated detection algorithm is used to identify IRIS burst profiles. Data from the Solar Dynamics Observatory's Helioseismic and Magnetic Imager are also used to provide context about the co-spatial line-of-sight magnetic field. Of the rasters studied, 36 were found to contain IRIS burst profiles. Five ARs (11850, 11909, 11916, 12104, and 12139) contained IRIS burst profiles in each raster that sampled them whilst one AR (11871) was found to contain no such spectra at any time. A total of 4019 IRIS burst profiles belonging to 752 connected objects, which we define as parent IRIS bursts, were identified. IRIS burst profiles were only detected within compact regions in each raster, with these regions appearing to increase in size as the host ARs aged. No systematic changes in the frequency of IRIS burst profiles or the spectral characteristic of IRIS burst profiles through time were found for these ARs. Finally, 93 % of parent IRIS bursts with areas between 1 arcsec^2 and 4 arcsec^2 occurred co-spatial to bi-poles in the photosphere. Overall, IRIS bursts have remarkably consistent spectral and spatial properties throughout the evolution of ARs. These events predominantly form within the cores of larger and more complex ARs, with the regions containing these events appearing to increase in size as the host region itself evolves.

12 pages, 7 figures, accepted by A&A

References in corpus (8)

• Hot Explosions in the Cool Atmosphere of the Sun
• Spectral observations of Ellerman bombs and fitting with a two-cloud model
• Small-Scale Structuring Of Ellerman Bombs at Solar Limb
• IRIS Burst Spectra Co-Spatial To A Quiet-Sun Ellerman-Like Brightening
• On The Relationship Between Magnetic Cancellation and UV Burst Formation
• 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. II. Calculating the most probable response in all spectral windows