Compact solar UV burst triggered in a magnetic field with a fan-spine topology
arXiv:1706.08059 · doi:10.1051/0004-6361/201730830
Abstract
Solar UV bursts are small-scale features that exhibit intermittent brightenings that are thought to be due to magnetic reconnection. They are observed abundantly in the chromosphere and transition region, in particular in active regions. We investigate in detail a UV burst related to a magnetic feature that is advected by the moat flow from a sunspot towards a pore. The moving feature is parasitic in that its magnetic polarity is opposite to that of the spot and the pore. We used UV spectroscopic and slit-jaw observations from the IRIS to identify and study chromospheric and transition region spectral signatures of said UV burst. To investigate the magnetic topology surrounding the UV burst, we used a two-hour-long time sequence of simultaneous line-of-sight magnetograms from the HMI and performed data-driven 3D magnetic field extrapolations by means of a magnetofrictional relaxation technique. We can connect UV burst signatures to the overlying EUV coronal loops observed by the AIA. The UV burst shows a variety of extremely broad line profiles indicating plasma flows in excess of 200 km s at times. The whole structure is divided into two spatially distinct zones of predominantly up- and downflows. The magnetic field extrapolations show a persistent fan-spine magnetic topology at the UV burst. The associated 3D magnetic null point exists at a height of about 500 km above the photosphere and evolves co-spatially with the observed UV burst. The EUV emission at the footpoints of coronal loops is correlated with the evolution of the underlying UV burst. The magnetic field around the null point is sheared by photospheric motions, triggering magnetic reconnection that ultimately powers the observed UV burst and energises the overlying coronal loops. The location of the null point suggests that the burst is triggered low in the solar chromosphere.
arXiv commentPublished in Astronomy & Astrophysics, abridged abstract
References in corpus (21)
- The Interface Region Imaging Spectrograph (IRIS)
- A Critical Assessment of Nonlinear Force-Free Field Modeling of the Solar Corona for Active Region 10953
- The Magnetic Topology of Solar Eruptions
- Hot Explosions in the Cool Atmosphere of the Sun
- Simulation of the Formation of a Solar Active Region
- Hot Spine Loops and the Nature of a Late-Phase Solar Flare
- Three-dimensional magnetic reconnection regimes: A review
- Fast magnetic reconnection in the solar chromosphere mediated by the plasmoid instability
- Ellerman bombs at high resolution III. Simultaneous observations with IRIS and SST
- Are IRIS bombs connected to Ellerman bombs?
- Ellerman bombs: fallacies, fads, usage
- Iris si iv line profiles: An indication for the plasmoid instability during small-scale magnetic reconnection on the sun
- Solar Coronal Loops Associated with Small-scale Mixed Polarity Surface Magnetic Fields
- Dynamics of the solar magnetic bright points derived from their horizontal motions
- Observational Signatures of Simulated Reconnection Events in the Solar Chromosphere and Transition Region
- Reconnection brightenings in the quiet solar photosphere
- A closer look at a coronal loop rooted in a sunspot umbra
- Limitations of force-free magnetic field extrapolations: revisiting basic assumptions
- On The Relationship Between Magnetic Cancellation and UV Burst Formation
- Resolving the Fan-Spine Reconnection Geometry of a Small-Scale Chromospheric Jet Event with the New Solar Telescope
- Nonlinear Force-Free Field Modeling of the Solar Magnetic Carpet and Comparison with SDO/HMI and Sunrise/IMaX Observations
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- A Cancellation Nanoflare Model for Solar Chromospheric and Coronal Heating
- Frequently Occurring Reconnection Jets from Sunspot Light Bridges
- Magnetic reconnection at the earliest stage of solar flux emergence
- Fine-scale explosive energy release at sites of prospective magnetic flux cancellation in the core of the solar active region observed by Hi-C 2.1, IRIS and SDO
- Plasmoid-mediated reconnection in solar UV bursts
- Round-trip Slipping Motion of the Circular Flare Ribbon Evidenced in a Fan-spine Jet
- The magnetic drivers of campfires seen by the Polarimetric and Helioseismic Imager (PHI) on Solar Orbiter
- Ultra-high-resolution Observations of Persistent Null-point Reconnection in the Solar Corona
- Extreme-ultraviolet bursts and nanoflares in the quiet-Sun transition region and corona
- Flame-like Ellerman Bombs and Their Connection to Solar UV Bursts
- IRIS observations of magnetic interactions in the solar atmosphere between pre-existing and emerging magnetic fields. I. Overall evolution
- A Cancellation Nanoflare Model for Solar Chromospheric and Coronal Heating II. 2D Theory and Simulations
- An observationally-constrained model of strong magnetic reconnection in the solar chromosphere. Atmospheric stratification and estimates of heating rates
- A Model for Coronal Hole Bright Points and Jets due to Moving Magnetic Elements
- A Magnetic Reconnection model for Hot Explosions in the Cool Atmosphere of the Sun
- IRIS observations of magnetic interactions in the solar atmosphere between pre-existing and emerging magnetic fields. II. UV emission properties
- Impulsive coronal heating during the interaction of surface magnetic fields in the lower solar atmosphere
- A Cancellation Nanoflare Model for Solar Chromospheric and Coronal Heating III. 3D Simulations and Atmospheric Response
- NuSTAR observations of a repeatedly microflaring active region
- Detections of Multi-Periodic Oscillations during a Circular Ribbon Flare
- Multi thermal atmosphere of a mini solar flare during magnetic reconnection observed with IRIS
- Solar Ultraviolet Bursts in a Coordinated Observation of IRIS, Hinode and SDO
- Heating of the solar chromosphere through current dissipation
- Energetics of magnetic transients in a solar active region plage
- ALMA observations of transient heating in a solar active region
- Observations of solar chromospheric heating at sub-arcsec spatial resolution
- Coronal Heating and Solar Wind Generation by Flux Cancellation Reconnection
- Chromospheric and coronal heating and jet acceleration due to reconnection driven by flux cancellation. I. At a three-dimensional current sheet
- Implosive collapse about magnetic null points: A quantitative comparison between 2D and 3D nulls
- Scalings Pertaining to Current Sheet Disruption Mediated by the Plasmoid Instability
- Modelling of asymmetric nanojets in coronal loops
- Spectropolarimetric Inversion in Four Dimensions with Deep Learning (SPIn4D): I. Overview, Magnetohydrodynamic Modeling, and Stokes Profile Synthesis
- Spectroscopic observation of a transition region network jet
- The Ellerman bomb and Ultraviolet burst triggered successively by an emerging magnetic flux rope
- Magnetic Topology of quiet-Sun Ellerman bombs and associated Ultraviolet brightenings
- Are the brightest coronal loops always rooted in mixed-polarity magnetic flux?
- A New Approach to Solar Flare Prediction
- Small-scale dynamic phenomena associated with interacting fan-spine topologies: quiet-Sun Ellerman bombs, UV brightenings, and chromospheric inverted-Y-shaped jets
- Three-dimensional Magnetic and Thermodynamic Structures of Solar Microflares
- Chromosphere of the quiet sun -- I. Shock and current-sheet dynamics and heating
- Resolving Interchange Reconnection Dynamics in a Fan-Spine-like Topology Observed by Solar Orbiter
- Emergence of internetwork magnetic fields through the solar atmosphere
- Nature of the energy source powering solar coronal loops driven by nanoflares