Investigating the Response of Loop Plasma to Nanoflare Heating Using RADYN Simulations

Fabio Reale, Milan Gošić, Pereira, Polito, Carlsson, De Pontieu, Carlsson, Paola Testa, Allred

Risultato della ricerca: Article

13 Citazioni (Scopus)

Abstract

We present the results of 1D hydrodynamic simulations of coronal loops that are subject to nanoflares, caused by either in situ thermal heating or nonthermal electron (NTE) beams. The synthesized intensity and Doppler shifts can be directly compared with Interface Region Imaging Spectrograph (IRIS) and Atmospheric Imaging Assembly (AIA) observations of rapid variability in the transition region (TR) of coronal loops, associated with transient coronal heating. We find that NTEs with high enough low-energy cutoff () deposit energy in the lower TR and chromosphere, causing blueshifts (up to ∼20 km s-1) in the IRIS Si iv lines, which thermal conduction cannot reproduce. The threshold value for the blueshifts depends on the total energy of the events (≈5 keV for 1024 erg, up to 15 keV for 1025 erg). The observed footpoint emission intensity and flows, combined with the simulations, can provide constraints on both the energy of the heating event and . The response of the loop plasma to nanoflares depends crucially on the electron density: significant Si iv intensity enhancements and flows are observed only for initially low-density loops (<109 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 94 ∗) 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 Mg ii chromospheric lines can help further constrain the properties of the heating mechanisms.
Lingua originaleEnglish
pagine (da-a)178-
Numero di pagine19
RivistaTHE ASTROPHYSICAL JOURNAL
Volume856
Stato di pubblicazionePublished - 2018

Fingerprint

heating
plasma
spectrographs
coronal loops
simulation
strands
erg
assembly
energy
Bryophytes
airglow
chromosphere
cut-off
moss
electron density
deposits
hydrodynamics
electron beams
conduction
thresholds

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cita questo

Reale, F., Gošić, M., Pereira, Polito, Carlsson, De Pontieu, ... Allred (2018). Investigating the Response of Loop Plasma to Nanoflare Heating Using RADYN Simulations. THE ASTROPHYSICAL JOURNAL, 856, 178-.

Investigating the Response of Loop Plasma to Nanoflare Heating Using RADYN Simulations. / Reale, Fabio; Gošić, Milan; Pereira; Polito; Carlsson; De Pontieu; Carlsson; Testa, Paola; Allred.

In: THE ASTROPHYSICAL JOURNAL, Vol. 856, 2018, pag. 178-.

Risultato della ricerca: Article

Reale, F, Gošić, M, Pereira, Polito, Carlsson, De Pontieu, Carlsson, Testa, P & Allred 2018, 'Investigating the Response of Loop Plasma to Nanoflare Heating Using RADYN Simulations', THE ASTROPHYSICAL JOURNAL, vol. 856, pagg. 178-.
Reale, Fabio ; Gošić, Milan ; Pereira ; Polito ; Carlsson ; De Pontieu ; Carlsson ; Testa, Paola ; Allred. / Investigating the Response of Loop Plasma to Nanoflare Heating Using RADYN Simulations. In: THE ASTROPHYSICAL JOURNAL. 2018 ; Vol. 856. pagg. 178-.
@article{15170eaa8ac74a25bf5af257d7fb2ed9,
title = "Investigating the Response of Loop Plasma to Nanoflare Heating Using RADYN Simulations",
abstract = "We present the results of 1D hydrodynamic simulations of coronal loops that are subject to nanoflares, caused by either in situ thermal heating or nonthermal electron (NTE) beams. The synthesized intensity and Doppler shifts can be directly compared with Interface Region Imaging Spectrograph (IRIS) and Atmospheric Imaging Assembly (AIA) observations of rapid variability in the transition region (TR) of coronal loops, associated with transient coronal heating. We find that NTEs with high enough low-energy cutoff () deposit energy in the lower TR and chromosphere, causing blueshifts (up to ∼20 km s-1) in the IRIS Si iv lines, which thermal conduction cannot reproduce. The threshold value for the blueshifts depends on the total energy of the events (≈5 keV for 1024 erg, up to 15 keV for 1025 erg). The observed footpoint emission intensity and flows, combined with the simulations, can provide constraints on both the energy of the heating event and . The response of the loop plasma to nanoflares depends crucially on the electron density: significant Si iv intensity enhancements and flows are observed only for initially low-density loops (<109 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 94 ∗) 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 Mg ii chromospheric lines can help further constrain the properties of the heating mechanisms.",
author = "Fabio Reale and Milan Gošić and Pereira and Polito and Carlsson and {De Pontieu} and Carlsson and Paola Testa and Allred",
year = "2018",
language = "English",
volume = "856",
pages = "178--",
journal = "THE ASTROPHYSICAL JOURNAL",
issn = "0004-637X",

}

TY - JOUR

T1 - Investigating the Response of Loop Plasma to Nanoflare Heating Using RADYN Simulations

AU - Reale, Fabio

AU - Gošić, Milan

AU - Pereira, null

AU - Polito, null

AU - Carlsson, null

AU - De Pontieu, null

AU - Carlsson, null

AU - Testa, Paola

AU - Allred, null

PY - 2018

Y1 - 2018

N2 - We present the results of 1D hydrodynamic simulations of coronal loops that are subject to nanoflares, caused by either in situ thermal heating or nonthermal electron (NTE) beams. The synthesized intensity and Doppler shifts can be directly compared with Interface Region Imaging Spectrograph (IRIS) and Atmospheric Imaging Assembly (AIA) observations of rapid variability in the transition region (TR) of coronal loops, associated with transient coronal heating. We find that NTEs with high enough low-energy cutoff () deposit energy in the lower TR and chromosphere, causing blueshifts (up to ∼20 km s-1) in the IRIS Si iv lines, which thermal conduction cannot reproduce. The threshold value for the blueshifts depends on the total energy of the events (≈5 keV for 1024 erg, up to 15 keV for 1025 erg). The observed footpoint emission intensity and flows, combined with the simulations, can provide constraints on both the energy of the heating event and . The response of the loop plasma to nanoflares depends crucially on the electron density: significant Si iv intensity enhancements and flows are observed only for initially low-density loops (<109 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 94 ∗) 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 Mg ii chromospheric lines can help further constrain the properties of the heating mechanisms.

AB - We present the results of 1D hydrodynamic simulations of coronal loops that are subject to nanoflares, caused by either in situ thermal heating or nonthermal electron (NTE) beams. The synthesized intensity and Doppler shifts can be directly compared with Interface Region Imaging Spectrograph (IRIS) and Atmospheric Imaging Assembly (AIA) observations of rapid variability in the transition region (TR) of coronal loops, associated with transient coronal heating. We find that NTEs with high enough low-energy cutoff () deposit energy in the lower TR and chromosphere, causing blueshifts (up to ∼20 km s-1) in the IRIS Si iv lines, which thermal conduction cannot reproduce. The threshold value for the blueshifts depends on the total energy of the events (≈5 keV for 1024 erg, up to 15 keV for 1025 erg). The observed footpoint emission intensity and flows, combined with the simulations, can provide constraints on both the energy of the heating event and . The response of the loop plasma to nanoflares depends crucially on the electron density: significant Si iv intensity enhancements and flows are observed only for initially low-density loops (<109 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 94 ∗) 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 Mg ii chromospheric lines can help further constrain the properties of the heating mechanisms.

UR - http://hdl.handle.net/10447/339477

UR - http://iopscience.iop.org/article/10.3847/1538-4357/aab49e/pdf

M3 - Article

VL - 856

SP - 178-

JO - THE ASTROPHYSICAL JOURNAL

JF - THE ASTROPHYSICAL JOURNAL

SN - 0004-637X

ER -