Chromospheric emission from nanoflare heating in RADYN simulations

Abstract

Heating signatures from small-scale magnetic reconnection events in the solar atmosphere have proven to be difficult to detect through observations. Numerical models that reproduce flaring conditions are essential in the understanding of how nanoflares may act as a heating mechanism of the corona. We study the effects of non-thermal electrons in synthetic spectra from 1D hydrodynamic RADYN simulations of nanoflare heated loops to investigate the diagnostic potential of chromospheric emission from small-scale events. The Mg II h and k, Ca II H and K, Ca II 854.2 nm, H-alpha and H-beta chromospheric lines were synthesised from various RADYN models of coronal loops subject to electron beams of nanoflare energies. The contribution function to the line intensity was computed to better understand how the atmospheric response to the non-thermal electrons affects the formation of spectral lines and the detailed shape of their spectral profiles. The spectral line signatures arising from the electron beams highly depend on the density of the loop and the lower cutoff energy of the electrons. Low-energy (5 keV) electrons deposit their energy in the corona and transition region, producing strong plasma flows that cause both redshifts and blueshifts of the chromospheric spectra. Higher-energy (10 and 15 keV) electrons deposit their energy in the lower transition region and chromosphere, resulting in increased emission from local heating. Our results indicate that effects from small-scale events can be observed with ground-based telescopes, expanding the list of possible diagnostics for the presence and properties of nanoflares.

References in corpus (20)

• The Interface Region Imaging Spectrograph (IRIS)
• The stellar atmosphere simulation code Bifrost
• 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
• 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
• 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
• The Formation of IRIS diagnostics. IV. The Mg II triplet lines as a new diagnostic for lower chromospheric heating
• Three-dimensional modeling of the Ca II H&K lines in the solar atmosphere
• Microflare Heating of a Solar Active Region Observed with NuSTAR, Hinode/XRT, and SDO/AIA
• What do iris observations of Mg II k tell us about the solar plage chromosphere?
• Investigating the response of loop plasma to nanoflare heating using RADYN simulations
• Accelerated electrons observed down to <7 keV in a NuSTAR solar microflare
• IRIS observations of short-term variability in moss associated with transient hot coronal loops
• NuSTAR observations of a repeatedly microflaring active region
• Accelerated particle beams in a 3D simulation of the quiet Sun
• Non-thermal electrons from solar nanoflares

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• A Statistical Study of IRIS Observational Signatures of Nanoflares and Non-thermal Particles
• High Resolution Observations of the Low Atmospheric Response to Small Coronal Heating Events in an Active Region Core
• Thermodynamic properties of small flares in the quiet Sun observed by H$\alpha$ and EUV: plasma motion of the chromosphere and time evolution of temperature/emission measure
• On Thermal Conduction in the Solar Atmosphere: An Analytical Solution for Nonlinear Diffusivity without Compact Support
• Chemical complexity in star formation induced by stellar feedback: cores shock-formed by the supernova remnant W44
• Accelerated particle beams in a 3D simulation of the quiet Sun. Lower atmospheric spectral diagnostics