Investigating the response of loop plasma to nanoflare heating using RADYN simulations

Abstract

We present the results of 1D hydrodynamic simulations of coronal loops which are subject to nanoflares, caused by either in-situ thermal heating, or non-thermal electrons (NTE) beams. The synthesized intensity and Doppler shifts can be directly compared with IRIS and AIA observations of rapid variability in the transition region (TR) of coronal loops, associated with transient coronal heating. We find that NTE with high enough low-energy cutoff (E${}_{\text{C}}$) deposit energy in the lower TR and chromosphere causing blueshifts (up to~$\sim$~20 km/s) in the \emph{IRIS} \siiv~lines, which thermal conduction cannot reproduce. The E${}_{\text{C}}$ threshold value for the blueshifts depends on the total energy of the events ($\approx$~5 keV for 10${}^{24}$ ergs, up to 15 keV for 10${}^{25}$ ergs). The observed footpoint emission intensity and flows, combined with the simulations, can provide constraints on both the energy of the heating event and E${}_{\text{C}}$. The response of the loop plasma to nanoflares depends crucially on the electron density: significant \siiv~intensity enhancements and flows are observed only for initially low-density loops ($<$~10${}^9$~cm${}^{-3}$). This provides a possible explanation of the relative scarcity of observations of significant moss variability. While the TR response to single heating episodes can be clearly observed, the predicted coronal emission (AIA 94Å) for single strands is below current detectability, and can only be observed when several strands are heated closely in time. Finally, we show that the analysis of the IRIS \mgii~chromospheric lines can help further constrain the properties of the heating mechanisms.

References in corpus (47)

• The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission
• The Interface Region Imaging Spectrograph (IRIS)
• On Solving the Coronal Heating Problem
• CHIANTI - An atomic database for Emission Lines. Version 8
• Heating of the Solar Chromosphere and Corona by Alfven Wave Turbulence
• Does a Non-Magnetic Solar Chromosphere Exist?
• A Unified Computational Model for Solar and Stellar Flares
• Key Aspects of Coronal Heating
• The formation of IRIS diagnostics II. The formation of the Mg II h&k lines in the solar atmosphere
• Evidence of Non-Thermal Particles in Coronal Loops Heated Impulsively by Nanoflares
• The formation of IRIS diagnostics I. A quintessential model atom of Mg II and general formation properties of the Mg II h&k lines
• Microflares and the Statistics of X-ray Flares
• The formation of IRIS diagnostics. III. Near-ultraviolet Spectra and Images
• Structure of solar coronal loops: from miniature to large-scale
• Observing coronal nanoflares in active region moss
• RH 1.5D: a massively parallel code for multi-level radiative transfer with partial frequency redistribution and Zeeman polarisation
• Using a Differential Emission Measure and Density Measurements in an Active Region Core to Test a Steady Heating Model
• Photometric and Thermal Cross-calibration of Solar EUV Instruments
• Simulations of the Mg II k and Ca II 8542 lines from an Alfvén Wave-heated flare chromosphere
• Evidence of widespread hot plasma in a non-flaring coronal active region from Hinode/XRT
• Non-equilibrium of Ionization and the Detection of Hot Plasma in Nanoflare-heated Coronal Loops
• Diagnosing the time-dependence of active region core heating from the emission measure: I. Low-frequency nanoflares
• Alfvénic Wave Heating of the Upper Chromosphere in Flares
• Temperature distribution of a non-flaring active region from simultaneous Hinode XRT and EIS observations
• What do iris observations of Mg II k tell us about the solar plage chromosphere?
• Hinode/EIS spectroscopic validation of very hot plasma imaged with Solar Dynamics Observatory in non-flaring active region cores
• Evidence for Steady Heating: Observations of an Active Region Core with Hinode and TRACE
• Stellar Activity and Coronal Heating: an overview of recent results
• IRIS Observations of the Mg II h & k Lines During a Solar Flare
• Forward modeling of emission in SDO/AIA passbands from dynamic 3D simulations
• Solar Dynamics Observatory discovers thin high temperature strands in coronal active regions
• Flows and Motions in Moss in the Core of a Flaring Active Region: Evidence for Steady Heating
• Observations and numerical models of solar coronal heating associated with spicules
• Benchmarking atomic data for astrophysics: a first look at the soft X-ray lines
• Testing EUV/X-ray Atomic Data for the Solar Dynamics Observatory
• Observation and Modeling of Coronal "Moss" With the EUV Imaging Spectrometer on Hinode
• High spatial resolution FeXII observations of solar active region
• A parameter study for modeling MgII h and k emission during solar flares
• Active Region Moss: Basic physical parameters and their temporal variation
• Diagnosing the time-dependence of active region core heating from the emission measure: II. Nanoflare trains
• Plasma sloshing in pulse-heated solar and stellar coronal loops
• Emission measure distribution in loops impulsively heated at the foot-points
• Determining heating time scales in solar active region cores from AIA/SDO Fe XVIII images
• The x-ray detectability of electron beams escaping from the sun
• Post-flare UV light curves explained with thermal instability of loop plasma
• EUV flickering of solar coronal loops: a new diagnostic of coronal heating
• Are all flare ribbons simply connected to the corona?

Cited by in corpus (40)

• The Properties of the Solar Corona and Its Connection to the Solar Wind
• Critical Science Plan for the Daniel K. Inouye Solar Telescope (DKIST)
• Probing the physics of the solar atmosphere with the Multi-slit Solar Explorer (MUSE): I. Coronal Heating
• Si IV Resonance Line Emission During Solar Flares: Non-LTE, Non-equilibrium, Radiation Transfer Simulations
• Probing the Physics of the Solar Atmosphere with the Multi-slit Solar Explorer (MUSE): II. Flares and Eruptions
• IRIS observations of short-term variability in moss associated with transient hot coronal loops
• A fully self-consistent model for solar flares
• 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
• Different Signatures of Chromospheric Evaporation in Two Solar Flares Observed with IRIS
• He I 10830 Å Dimming During Solar Flares, I. The Crucial Role of Non-Thermal Collisional Ionisations
• Solar Flare Arcade Modelling: Bridging the gap from 1D to 3D Simulations of Optically Thin Radiation
• Large-amplitude quasi-periodic pulsations as evidence of impulsive heating in hot transient loop systems detected in the EUV with SDO/AIA
• Solar Flare Ribbon Fronts I: Constraining flare energy deposition with IRIS spectroscopy
• IRIS Si IV Line Profiles at Flare Ribbons as Indications of Chromospheric Condensation
• Correlated Spatiotemporal Evolution of Extreme-Ultraviolet Ribbons and Hard X-rays in a Solar Flare
• Joint X-ray, EUV and UV Observations of a Small Microflare
• Impulsive coronal heating from large-scale magnetic rearrangements: from IRIS to SDO/AIA
• Magnetic loops above a small flux-emerging region observed by IRIS, Hinode and SDO
• Prospects of Detecting Non-thermal Protons in Solar Flares via Lyman Line Spectroscopy: Revisiting the Orrall-Zirker Effect
• Accelerated particle beams in a 3D simulation of the quiet Sun
• The Response of the Lyman-Alpha Line in Different Flare Heating Models
• Intrusion of Magnetic Peninsula toward the Neighboring Opposite-polarity Region That Triggers the Largest Solar Flare in Solar Cycle 24
• Diagnosing the Optically Thick/Thin Features Using the Intensity Ratio of Si IV Resonance Lines in Solar Flares
• Simultaneous Observations of Chromospheric Evaporation and Condensation during a C-class Flare
• A Statistical Study of IRIS Observational Signatures of Nanoflares and Non-thermal Particles
• Quantifying the Influence of Key Physical Processes on the Formation of Emission Lines Observed by IRIS: I. Non-Equilibrium Ionization and Density-Dependent Rates
• Chromospheric emission from nanoflare heating in RADYN simulations
• Solar flares in the Solar Orbiter era: Short-exposure EUI/FSI observations of STIX flares
• An approximate recipe of chromospheric radiative losses for solar flares
• Properties of the diffuse emission around warm loops in solar active regions
• Morphological evidence for nanoflares heating warm loops in the solar corona
• High Resolution Observations of the Low Atmospheric Response to Small Coronal Heating Events in an Active Region Core
• Energy distribution of small-scale flares derived using genetic algorithm
• On Thermal Conduction in the Solar Atmosphere: An Analytical Solution for Nonlinear Diffusivity without Compact Support
• A new view of the solar interface region from the Interface Region Imaging Spectrograph (IRIS)
• Inevitable consequences of ion-neutral damping of intermediate MHD waves in Sun-like stars
• Observational Evidence Linking Loop Length and Thermal-Nonthermal Peak Timing in Solar Flares
• 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
• SolO/EUI Observations of Ubiquitous Fine-scale Bright Dots in an Emerging Flux Region: Comparison with a Bifrost MHD Simulation