Origin of the 30 THz Emission Detected During the Solar Flare on 2012 March 13 at 17:20 UT

Solar observations in the infrared domain can bring important clues on the response of the low solar atmosphere to primary energy released during flares. At present, the infrared continuum has been detected at 30 THz (10 μm) in only a few flares. SOL2012-03-13, which is one of these flares, has been...

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Detalles Bibliográficos
Publicado: 2015
Materias:
Chromosphere, models
Heating, chromospheric
Heating, in flares
Radio bursts, microwave
X-ray burst, spectrum
X-ray bursts, association with flares
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00380938_v290_n10_p2809_Trottet
http://hdl.handle.net/20.500.12110/paper_00380938_v290_n10_p2809_Trottet
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling paper:paper_00380938_v290_n10_p2809_Trottet2023-06-08T15:02:51Z Origin of the 30 THz Emission Detected During the Solar Flare on 2012 March 13 at 17:20 UT Chromosphere, models Heating, chromospheric Heating, in flares Radio bursts, microwave X-ray burst, spectrum X-ray bursts, association with flares Solar observations in the infrared domain can bring important clues on the response of the low solar atmosphere to primary energy released during flares. At present, the infrared continuum has been detected at 30 THz (10 μm) in only a few flares. SOL2012-03-13, which is one of these flares, has been presented and discussed in Kaufmann et al. (Astrophys. J.768, 134, 2013). No firm conclusions were drawn on the origin of the mid-infrared radiation. In this work we present a detailed multi-frequency analysis of the SOL2012-03-13 event, including observations at radio-millimeter and submillimeter wavelengths, in hard X-rays (HXR), gamma-rays (GR), Hα, and white light. The HXR/GR spectral analysis shows that SOL2012-03-13 is a GR line flare and allows estimating the numbers of and energy contents in electrons, protons, and α particles produced during the flare. The energy spectrum of the electrons producing the HXR/GR continuum is consistent with a broken power-law with an energy break at (Formula presented.). We show that the high-energy part ((Formula presented.)) of this distribution is responsible for the high-frequency radio emission ((Formula presented.)) detected during the flare. By comparing the 30 THz emission expected from semi-empirical and time-independent models of the quiet and flare atmospheres, we find that most ((Formula presented.)) of the observed 30 THz radiation can be attributed to thermal free–free emission of an optically thin source. Using the F2 flare atmospheric model (Machado et al. in Astrophys. J.242, 336, 1980), this thin source is found to be at temperatures T (Formula presented.) and is located well above the minimum temperature region. We argue that the chromospheric heating, which results in 80 % of the 30 THz excess radiation, can be due to energy deposition by nonthermal flare-accelerated electrons, protons, and α particles. The remaining 20 % of the 30 THz excess emission is found to be radiated from an optically thick atmospheric layer at T (Formula presented.), below the temperature minimum region, where direct heating by nonthermal particles is insufficient to account for the observed infrared radiation. © 2015, Springer Science+Business Media Dordrecht. 2015 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00380938_v290_n10_p2809_Trottet http://hdl.handle.net/20.500.12110/paper_00380938_v290_n10_p2809_Trottet
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Chromosphere, models
Heating, chromospheric
Heating, in flares
Radio bursts, microwave
X-ray burst, spectrum
X-ray bursts, association with flares
spellingShingle Chromosphere, models
Heating, chromospheric
Heating, in flares
Radio bursts, microwave
X-ray burst, spectrum
X-ray bursts, association with flares
Origin of the 30 THz Emission Detected During the Solar Flare on 2012 March 13 at 17:20 UT
topic_facet Chromosphere, models
Heating, chromospheric
Heating, in flares
Radio bursts, microwave
X-ray burst, spectrum
X-ray bursts, association with flares
description Solar observations in the infrared domain can bring important clues on the response of the low solar atmosphere to primary energy released during flares. At present, the infrared continuum has been detected at 30 THz (10 μm) in only a few flares. SOL2012-03-13, which is one of these flares, has been presented and discussed in Kaufmann et al. (Astrophys. J.768, 134, 2013). No firm conclusions were drawn on the origin of the mid-infrared radiation. In this work we present a detailed multi-frequency analysis of the SOL2012-03-13 event, including observations at radio-millimeter and submillimeter wavelengths, in hard X-rays (HXR), gamma-rays (GR), Hα, and white light. The HXR/GR spectral analysis shows that SOL2012-03-13 is a GR line flare and allows estimating the numbers of and energy contents in electrons, protons, and α particles produced during the flare. The energy spectrum of the electrons producing the HXR/GR continuum is consistent with a broken power-law with an energy break at (Formula presented.). We show that the high-energy part ((Formula presented.)) of this distribution is responsible for the high-frequency radio emission ((Formula presented.)) detected during the flare. By comparing the 30 THz emission expected from semi-empirical and time-independent models of the quiet and flare atmospheres, we find that most ((Formula presented.)) of the observed 30 THz radiation can be attributed to thermal free–free emission of an optically thin source. Using the F2 flare atmospheric model (Machado et al. in Astrophys. J.242, 336, 1980), this thin source is found to be at temperatures T (Formula presented.) and is located well above the minimum temperature region. We argue that the chromospheric heating, which results in 80 % of the 30 THz excess radiation, can be due to energy deposition by nonthermal flare-accelerated electrons, protons, and α particles. The remaining 20 % of the 30 THz excess emission is found to be radiated from an optically thick atmospheric layer at T (Formula presented.), below the temperature minimum region, where direct heating by nonthermal particles is insufficient to account for the observed infrared radiation. © 2015, Springer Science+Business Media Dordrecht.
title Origin of the 30 THz Emission Detected During the Solar Flare on 2012 March 13 at 17:20 UT
title_short Origin of the 30 THz Emission Detected During the Solar Flare on 2012 March 13 at 17:20 UT
title_full Origin of the 30 THz Emission Detected During the Solar Flare on 2012 March 13 at 17:20 UT
title_fullStr Origin of the 30 THz Emission Detected During the Solar Flare on 2012 March 13 at 17:20 UT
title_full_unstemmed Origin of the 30 THz Emission Detected During the Solar Flare on 2012 March 13 at 17:20 UT
title_sort origin of the 30 thz emission detected during the solar flare on 2012 march 13 at 17:20 ut
publishDate 2015
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00380938_v290_n10_p2809_Trottet
http://hdl.handle.net/20.500.12110/paper_00380938_v290_n10_p2809_Trottet
_version_ 1768542258981765120

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