The magnetic drivers of campfires seen by the Polarimetric and Helioseismic Imager (PHI) on Solar Orbiter
arXiv:2202.13859 · doi:10.1051/0004-6361/202142873
Abstract
The Extreme Ultraviolet Imager (EUI) on board the Solar Orbiter (SO) spacecraft observed small extreme ultraviolet (EUV) bursts, termed campfires, that have been proposed to be brightenings near the apexes of low-lying loops in the quiet-Sun atmosphere. The underlying magnetic processes driving these campfires are not understood. During the cruise phase of SO and at a distance of 0.523\,AU from the Sun, the Polarimetric and Helioseismic Imager on Solar Orbiter (SO/PHI) observed a quiet-Sun region jointly with SO/EUI, offering the possibility to investigate the surface magnetic field dynamics underlying campfires at a spatial resolution of about 380~km. In 71\% of the 38 isolated events, campfires are confined between bipolar magnetic features, which seem to exhibit signatures of magnetic flux cancellation. The flux cancellation occurs either between the two main footpoints, or between one of the footpoints of the loop housing the campfire and a nearby opposite polarity patch. In one particularly clear-cut case, we detected the emergence of a small-scale magnetic loop in the internetwork followed soon afterwards by a campfire brightening adjacent to the location of the linear polarisation signal in the photosphere, that is to say near where the apex of the emerging loop lays. The rest of the events were observed over small scattered magnetic features, which could not be identified as magnetic footpoints of the campfire hosting loops. The majority of campfires could be driven by magnetic reconnection triggered at the footpoints, similar to the physical processes occurring in the burst-like EUV events discussed in the literature. About a quarter of all analysed campfires, however, are not associated to such magnetic activity in the photosphere, which implies that other heating mechanisms are energising these small-scale EUV brightenings.
References in corpus (18)
- The Solar Orbiter mission -- Science overview
- Hot Explosions in the Cool Atmosphere of the Sun
- Emergence of Small-Scale Magnetic Loops in the Quiet Sun Internetwork
- Emergence of small-scale magnetic loops through the quiet solar atmosphere
- The Solar Orbiter Science Activity Plan: translating solar and heliospheric physics questions into action
- Transient small-scale brightenings in the quiet solar corona: a model for campfires observed with Solar Orbiter
- Solar Coronal Loops Associated with Small-scale Mixed Polarity Surface Magnetic Fields
- Structure and Dynamics of Isolated Internetwork Ca II H Bright Points Observed by Sunrise
- The usefulness of analytic response functions
- Compact solar UV burst triggered in a magnetic field with a fan-spine topology
- Magnetic field emergence in quiet Sun granules
- Extreme-ultraviolet bursts and nanoflares in the quiet-Sun transition region and corona
- On The Relationship Between Magnetic Cancellation and UV Burst Formation
- Capturing transient plasma flows and jets in the solar corona
- Impulsive coronal heating during the interaction of surface magnetic fields in the lower solar atmosphere
- Statistical evolution of quiet-Sun small scale magnetic features using Sunrise observations
- Miniature loops in the solar corona
- Reciprocatory magnetic reconnection in a coronal bright point
Cited by in corpus (25)
- Small-scale dynamos: From idealized models to solar and stellar applications
- Solar Orbiter and SDO Observations, and Bifrost MHD Simulations of Small-scale Coronal Jets
- Temperature of Solar Orbiter/EUI quiet Sun small scale brightenings: evidence for a cooler component
- Imaging and spectroscopic observations of extreme-ultraviolet brightenings using EUI and SPICE on board Solar Orbiter
- EUV brightenings in the quiet-Sun: Signatures in spectral and imaging data from the Interface Region Imaging Spectrograph
- Coronal Heating and Solar Wind Generation by Flux Cancellation Reconnection
- Fleeting Small-scale Surface Magnetic Fields Build the Quiet-Sun Corona
- Spectroscopic evidence of cool plasma in quiet Sun HRIEUV small scale brightenings
- Automatic detection of small-scale EUV brightenings observed by the Solar Orbiter/EUI
- Spatial distributions of EUV brightenings in the quiet-Sun
- Small-scale loops heated to transition region temperatures and their chromospheric signatures in the simulated solar atmosphere
- Small-scale magnetic flux emergence preceding a chain of energetic solar atmospheric events
- Thin coronal jets and plasmoid-mediated reconnection: Insights from Solar Orbiter observations and Bifrost simulations
- Extreme-ultraviolet transient brightenings in the quiet-Sun corona : Closest-perihelion observations with Solar Orbiter/EUI
- Magnetic Topology of quiet-Sun Ellerman bombs and associated Ultraviolet brightenings
- Quasi-periodic pulsations in extreme-ultraviolet brightenings
- 3D structures of the base of small-scale recurrent jets revealed by Solar orbiter
- Coronal voids and their magnetic nature
- The nature of small scale EUV solar brightenings investigated as impulsive heating of short loops in 1D hydrododynamics simulations
- Investigating explosive events in a 3D quiet-Sun model: Transition region and coronal response
- Heating in the Solar Atmosphere at a Fin Current Sheet Driven by Magnetic Flux Cancellation
- Data-constrained 3D MHD Simulation of a Spiral Jet Caused by an Unstable Flux Rope Embedded in Fan-spine Configuration
- Accessing the fine temporal scale of EUV brightenings and their quasi-periodic pulsations: 1 second cadence observations by Solar Orbiter/EUI
- The effect of shear flow on the resistive tearing instability
- Magnetic structure of coronal dark halos