Evidence of Non-Thermal Particles in Coronal Loops Heated Impulsively by Nanoflares

Abstract

The physical processes causing energy exchange between the Sun's hot corona and its cool lower atmosphere remain poorly understood. The chromosphere and transition region (TR) form an interface region between the surface and the corona that is highly sensitive to the coronal heating mechanism. High resolution observations with the Interface Region Imaging Spectrograph (IRIS) reveal rapid variability (about 20 to 60 seconds) of intensity and velocity on small spatial scales at the footpoints of hot dynamic coronal loops. The observations are consistent with numerical simulations of heating by beams of non-thermal electrons, which are generated in small impulsive heating events called "coronal nanoflares". The accelerated electrons deposit a sizable fraction of their energy in the chromosphere and TR. Our analysis provides tight constraints on the properties of such electron beams and new diagnostics for their presence in the nonflaring corona.

arXiv commentPublished in Science on October 17: http://www.sciencemag.org/content/346/6207/1255724 . 26 pages, 10 figures. Movies are available at: http://www.lmsal.com/~ptesta/iris_science_mov/

References in corpus (37)

• The chemical composition of the Sun
• The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission
• The Interface Region Imaging Spectrograph (IRIS)
• An Observational Overview of Solar Flares
• On Solving the Coronal Heating Problem
• Heating of the Solar Chromosphere and Corona by Alfven Wave Turbulence
• Impulsive phase flare energy transport by large-scale Alfven waves and the electron acceleration problem
• Radiative Hydrodynamic Models of the Optical and Ultraviolet Emission from Solar Flares
• Does a Non-Magnetic Solar Chromosphere Exist?
• Implications of X-ray Observations for Electron Acceleration and Propagation in Solar Flares
• The formation of IRIS diagnostics II. The formation of the Mg II h&k lines in the solar atmosphere
• Stochastic Acceleration of Electrons and Protons. I. Acceleration by Parallel Propagating Waves
• RHESSI Microflare Statistics II. X-ray Imaging, Spectroscopy & Energy Distributions
• Recent Advances in Understanding Particle Acceleration Processes in Solar Flares
• Deducing Electron Properties From Hard X-Ray Observations
• Microflares and the Statistics of X-ray Flares
• Observing coronal nanoflares in active region moss
• Evidence for Widespread Cooling in an Active Region Observed with the SDO Atmospheric Imaging Assembly
• Radiative Hydrodynamic Models of Optical and Ultraviolet Emission from M Dwarf Flares
• Kappa Distribution Model for Hard X-Ray Coronal Sources of Solar Flares
• Coronal Loops: Observations and Modeling of Confined Plasma
• Local re-acceleration and a modified thick target model of solar flare electrons
• Evidence of widespread hot plasma in a non-flaring coronal active region from Hinode/XRT
• Propagation of Alfvénic Waves From Corona to Chromosphere and Consequences for Solar Flares
• Particle acceleration mechanisms
• Fast approximation of angle-dependent partial redistribution in moving atmospheres
• Hinode/EIS spectroscopic validation of very hot plasma imaged with Solar Dynamics Observatory in non-flaring active region cores
• Combined Modeling of Acceleration, Transport, and Hydrodynamic Response in Solar Flares: I. The Numerical Model
• Forward modeling of emission in SDO/AIA passbands from dynamic 3D simulations
• Solar Dynamics Observatory discovers thin high temperature strands in coronal active regions
• Constraining the hard X-ray properties of the quiet Sun with new RHESSI observations
• Investigating the reliability of coronal emission measure distribution diagnostics using 3D radiative MHD simulations
• Testing EUV/X-ray Atomic Data for the Solar Dynamics Observatory
• The x-ray detectability of electron beams escaping from the sun
• Spectroscopic Observations of Fe XVIII in Solar Active Regions
• Fe IX Calculations for the Solar Dynamics Observatory
• Modifications of thick-target model: re-acceleration of electron beams by static and stochastic electric fields

Cited by in corpus (106)

• Hot Explosions in the Cool Atmosphere of the Sun
• The Properties of the Solar Corona and Its Connection to the Solar Wind
• Solar science with the Atacama Large Millimeter/submillimeter Array - A new view of our Sun
• Recent advances in coronal heating
• Are IRIS bombs connected to Ellerman bombs?
• Critical Science Plan for the Daniel K. Inouye Solar Telescope (DKIST)
• The Multi-slit Approach to Coronal Spectroscopy with the Multi-slit Solar Explorer (MUSE)
• Probing the physics of the solar atmosphere with the Multi-slit Solar Explorer (MUSE): I. Coronal Heating
• Alfvénic Wave Heating of the Upper Chromosphere in Flares
• Microflare Heating of a Solar Active Region Observed with NuSTAR, Hinode/XRT, and SDO/AIA
• Damping of slow magnetoacoustic oscillations by the misbalance between heating and cooling processes in the solar corona
• Non-Equilibrium Processes in the Solar Corona, Transition Region, Flares, and Solar Wind \textit{(Invited Review)}
• Investigating the response of loop plasma to nanoflare heating using RADYN simulations
• Stellar Activity and Coronal Heating: an overview of recent results
• KAPPA: A Package for Synthesis of optically thin spectra for the non-Maxwellian kappa-distributions based on the CHIANTI database
• Probing the Physics of the Solar Atmosphere with the Multi-slit Solar Explorer (MUSE): II. Flares and Eruptions
• Solar coronal heating from small-scale magnetic braids
• Non-Maxwellian analysis of the transition-region line profiles observed by the Interface Region Imaging Spectrograph
• The first X-ray imaging spectroscopy of quiescent solar active regions with NuSTAR
• IRIS observations of short-term variability in moss associated with transient hot coronal loops
• High spatial resolution FeXII observations of solar active region
• Transition Region and Chromospheric Signatures of Impulsive Heating Events. I. Observations
• The effects of numerical resolution, heating timescales and background heating on thermal non-equilibrium in coronal loops
• On the Magnetic and Energy Characteristics of Recurrent Homologous Jets from An Emerging Flux
• Electron kinetics inferred from observations of microwave bursts during edge localised modes in the Mega-Amp Spherical Tokamak
• Coronal rain in randomly heated arcades
• Plasma sloshing in pulse-heated solar and stellar coronal loops
• The Role of Partial Ionization Effects in the Chromosphere
• Transition Region and Chromospheric Signatures of Impulsive Heating Events. II. Modeling
• The Atmospheric Response to High Nonthermal Electron Beam Fluxes in Solar Flares. II. Hydrogen Broadening Predictions for Solar Flare Observations with the Daniel K. Inouye Solar Telescope
• A Simple Method for Modeling Collision Processes in Plasmas with a Kappa Energy Distribution
• Time Dependent Non-Equilibrium Ionization of Transition Region Lines Observed with IRIS
• Observations and Modelling of the Pre-Flare Period of the 29 March 2014 X1 Flare
• Corona and XUV emission modelling of the Sun and Sun-like stars
• Combined Modeling of Acceleration, Transport, and Hydrodynamic Response in Solar Flares. II. Inclusion of Radiative Transfer with RADYN
• First radio evidence for impulsive heating contribution to the quiet solar corona
• Imaging and Spectroscopic Observations of a Transient Coronal Loop: Evidence for the Non-Maxwellian $\kappa$-Distributions
• Large-amplitude quasi-periodic pulsations as evidence of impulsive heating in hot transient loop systems detected in the EUV with SDO/AIA
• Impulsive coronal heating during the interaction of surface magnetic fields in the lower solar atmosphere
• Self-consistent 3D radiative MHD simulations of coronal rain formation and evolution
• Modelling the solar transition region using an adaptive conduction method
• The Duration of Energy Deposition on Unresolved Flaring Loops in the Solar Corona
• Solar Flare Ribbon Fronts I: Constraining flare energy deposition with IRIS spectroscopy
• Correlated Spatiotemporal Evolution of Extreme-Ultraviolet Ribbons and Hard X-rays in a Solar Flare
• Observational study of chromospheric heating by acoustic waves
• Joint X-ray, EUV and UV Observations of a Small Microflare
• Chromospheric heating by acoustic waves compared to radiative cooling
• Electron Two-stream Instability and Its Application in Solar and Heliophysics
• Observations of instability-driven nanojets
• NuSTAR Observation of a Minuscule Microflare in a Solar Active Region
• Impulsive coronal heating from large-scale magnetic rearrangements: from IRIS to SDO/AIA
• The Magnetic Properties of Heating Events on High-Temperature Active Region Loops
• Energetics of magnetic transients in a solar active region plage
• EUV fine structure and variability associated with coronal rain revealed by Solar Orbiter/EUI HRIEUV and SPICE
• Time-resolved emission from bright hot pixels of an active region observed in the EUV band with SDO/AIA and multi-stranded loop modeling
• Observation and Modeling of Chromospheric Evaporation in a Coronal Loop Related to Active Region Transient Brightening
• Accelerated particle beams in a 3D simulation of the quiet Sun
• Is It Small-scale Weak Magnetic Activity That Effectively Heats the Upper Solar Atmosphere?
• Non-thermal electrons from solar nanoflares
• Periodicities in an active region correlated with Type III radio bursts observed by Parker Solar Probe
• Flare particle acceleration in the interaction of twisted coronal flux ropes
• Particle dynamics in a non-flaring solar active region model
• Diagnosing the Optically Thick/Thin Features Using the Intensity Ratio of Si IV Resonance Lines in Solar Flares
• Energetics of small electron acceleration episodes in the solar corona from radio noise storm observations
• Suppression of Hydrogen Emission in an X-class White-light Solar Flare
• Modelling of asymmetric nanojets in coronal loops
• A Statistical Study of IRIS Observational Signatures of Nanoflares and Non-thermal Particles
• The UV spectrum of the Ultracool Dwarf LSR J1835+3259 observed with the Hubble Space Telescope
• Transient Formation of Loops in the Core of an Active Region
• Non-equilibrium ionization by a periodic electron beam. I. Synthetic coronal spectra and implications for interpretation of observations
• Quantifying the Influence of Key Physical Processes on the Formation of Emission Lines Observed by IRIS: I. Non-Equilibrium Ionization and Density-Dependent Rates
• IRIS observations of chromospheric heating by acoustic waves in solar quiet and active regions
• Plasma heating and nanoflare caused by slow-mode wave in a coronal loop
• Chromospheric emission from nanoflare heating in RADYN simulations
• Thermal characteristics and the differential emission measure distribution during a B8.3 flare on July 04, 2009
• On the faintest solar coronal hard X-rays observed with FOXSI
• A magnetic avalanche as the central engine powering a solar flare
• Quiet Sun flux rope formation via incomplete Taylor relaxation
• Spectroscopic and imaging observations of transient hot and cool loops by IRIS and SDO
• Evidence for two-loop interaction from IRIS and SDO observations of penumbral brightenings
• Synthetic IRIS spectra of the solar transition region: Effect of high-energy tails
• How Nanoflares Produce Kinetic Waves, Nano-Type III Radio Bursts, and Non-Thermal Electrons in the Solar Wind
• Coronal energy release by MHD avalanches III. Identification of a reconnection outflow from a nanoflare
• Are the brightest coronal loops always rooted in mixed-polarity magnetic flux?
• Thermal and Non-Thermal Properties of Active Region Recurrent Coronal Jets
• Are all flare ribbons simply connected to the corona?
• Energy distribution of small-scale flares derived using genetic algorithm
• High Resolution Observations of the Low Atmospheric Response to Small Coronal Heating Events in an Active Region Core
• Multifrequency microwave imaging of weak transients from the quiet solar corona
• Transition region bright dots in active regions observed by the Interface Region Imaging Spectrograph
• Can the Kappa-distributed electron energies account for the intensity ratios of O II lines in photoionized gaseous nebulae?
• Penumbral brightening events observed in AR NOAA 12546
• An in-depth analysis of quiet-Sun IRIS Brightenings
• On Thermal Conduction in the Solar Atmosphere: An Analytical Solution for Nonlinear Diffusivity without Compact Support
• Coronal heating problem solution by means of axion origin photons
• Common Origin of Kinetic Scale Turbulence and the Electron Halo in the Solar Wind -- Connection to Nanoflares
• Magnetic Imaging of the Outer Solar Atmosphere (MImOSA): Unlocking the driver of the dynamics in the upper solar atmosphere
• A new view of the solar interface region from the Interface Region Imaging Spectrograph (IRIS)
• On the Nature of Nonthermal Broadening of Spectral Lines Observed by IRIS
• Energy conversion rate of an active region transient brightening estimated by a spectroscopic observation of Hinode
• Accelerated particle beams in a 3D simulation of the quiet Sun. Lower atmospheric spectral diagnostics
• Variation in the intensity ratio at each wavelength point of the Si iv 1394/1403 Å lines. Spectral diagnostics of a bifurcated eruption
• Nature of the energy source powering solar coronal loops driven by nanoflares
• Reconstruction of photospheric velocity fields from highly corrupted data
• SolO/EUI Observations of Ubiquitous Fine-scale Bright Dots in an Emerging Flux Region: Comparison with a Bifrost MHD Simulation
• The Quiet-Sun DEM Under Kappa: Diagnostic Degeneracy and the Failure of the Conductive Closure