Comparison of 30 THz impulsive burst time development to microwaves, H<i>α</i>, EUV, and GOES soft X-rays

Miteva, R.; Kaufmann, P.; Cabezas, Denis P.; Cassiano, M. M.; Fernandes, L. O. T.; Freeland, S.; Karlický, M.; Kerdraon, A.; Kudaka, A. S.; Luoni, M. L.; Marcon, R.; Raulin, J. P.; Trottet, G.; White, S. M.

doi:10.1051/0004-6361/201425520

Cited by 5 publications

(7 citation statements)

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“…To summarize our findings, our observations endorse the similarities between the light curves at mid‐IR frequencies and WL previously reported (Kaufmann et al, , ; Miteva et al, ; Penn et al, ), although these emissions have different origins. Another important result is that the derived flux at mid‐IR is well above the obtained density flux at submillimeter wavelengths and detected even with a commercial camera in the focus of a small telescope.…”

Section: Discussionsupporting

confidence: 93%

“…The flux at both wavelengths is of the same order, lending support to a thermal optically thin origin, a conclusion further reinforced by results of radiative hydrodynamic simulations by Simões et al (). Two other events were registered at 10 μm: SOL2014‐08‐01T14:47 (Miteva et al, ) and SOL2014‐10‐27T14:22 (Kaufmann et al, ), the last one classified as X2.…”

Section: Introductionmentioning

confidence: 99%

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The 6 September 2017 X9 Super Flare Observed From Submillimeter to Mid‐IR

et al. 2018

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Active Region 12673 is the most productive active region of solar cycle 24: in a few days of early September 2017, four X‐class and 27 M‐class flares occurred. SOL2017‐09‐06T12:00, an X9.3 flare also produced a two‐ribbon white light emission across the sunspot detected by Solar Dynamics Orbiter/Helioseismic and Magnetic Imager. The flare was observed at 212 and 405 GHz with the arcminute‐sized beams of the Solar Submillimeter Telescope focal array while making a solar map and at 10 μm, with a 17 arcsec diffraction‐limited infrared camera. Images at 10 μm revealed that the sunspot gradually increased in brightness while the event proceeded, reaching a temperature similar to quiet Sun values. From the images we derive a lower bound limit of 180‐K flare peak excess brightness temperature or 7,000 sfu if we consider a similar size as the white light source. The rising phase of mid‐IR and white light is similar, although the latter decays faster, and the maximum of the mid‐IR and white light emission is ∼200 s delayed from the 15.4‐GHz peak occurrence. The submillimeter spectrum has a different origin than that of microwaves from 1 to 15 GHz, although it is not possible to draw a definitive conclusion about its emitting mechanism.

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Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

The 6 September 2017 X9 Super Flare Observed From Submillimeter to Mid‐IR

et al. 2018

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“…Telescopes observing in the visible band with higher sensitivity, such as the Daniel K. Inouye Solar Telescope (DKIST, Rast et al 2021) or the European Solar Telescope (EST, Schlichenmaier et al 2019), should be able to detect the flare excess (or lack thereof) in white-light for this kind of weak events (Jess et al 2008). -The similar behavior between the time profiles of 30 THz and AIA1700, first reported in Miteva et al (2016) for an impulsive GOES M2 class flare, is confirmed in our work for the thermal-driven event analyzed here. Both emissions have a chromospheric origin.…”

Section: Discussionsupporting

confidence: 90%

A solar flare driven by thermal conduction observed in mid-infrared

López,

de Castro,

Mandrini

et al. 2021

Preprint

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Context. The mid-infrared (mid-IR) range has been mostly unexplored for the investigation of solar flares. It is only recently that new mid-IR flare observations have begun opening a new window into the response and evolution of the solar chromosphere. These new observations have been mostly performed by the AR30T and BR30T telescopes that are operating in Argentina and Brazil, respectively. Aims. We present the analysis of SOL2019-05-15T19:24, a GOES class C2.0 solar flare observed at 30 THz (10 µm) by the groundbased telescope AR30T. Our aim is to characterize the evolution of the flaring atmosphere and the energy transport mechanism in the context of mid-IR emission. Methods. We performed a multi-wavelength analysis of the event by complementing the mid-IR data with diverse ground-and space-based data from the Solar Dynamics Observatory (SDO), the H-α Solar Telescope for Argentina (HASTA), and the Expanded Owens Valley Solar Array (EOVSA). Our study includes the analysis of the magnetic field evolution of the flaring region and of the development of the flare. Results. The mid-IR images from AR30T show two bright and compact flare sources that are spatially associated with the flare kernels observed in ultraviolet (UV) by SDO. We confirm that the temporal association between mid-IR and UV fluxes previously reported for strong flares is also observed for this small flare. The EOVSA microwave data revealed flare spectra consistent with thermal free-free emission, which lead us to dismiss the existence of a significant number of non-thermal electrons. We thus consider thermal conduction as the primary mechanism responsible for energy transport. Our estimates for the thermal conduction energy and total radiated energy fall within the same order of magnitude, reinforcing our conclusions.

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“…These studies have reported a good temporal or spatial agreement (or both) between mid-IR data and emission from other wavelengths, such as: microwaves (MW; Kaufmann et al 2013), hard X-rays (HXR; Kaufmann et al 2013;Penn et al 2016), white-light (Kaufmann et al 2013;Penn et al 2016;Giménez de Castro et al 2018), and ultraviolet (UV) emission (Miteva et al 2016). Moreover, when compared to the flare emission in the submillimeter domain, the mid-IR presents higher flux density values.…”

Section: Introductionmentioning

confidence: 90%

“…The analysis of solar flares in mid-IR wavelengths, λ > 5 µm, is a new area of research with only a few events reported in the literature thus far. Kaufmann et al (2013Kaufmann et al ( , 2015, Miteva et al (2016) and Giménez de Castro et al (2018) used commercial IR cameras in the focus of small telescopes at room temperature with apertures ranging from 10 to 20 cm that produce images with diffraction limits around 15 and sensors centered at λ = 10 µm (ν = 30 THz). These observations revealed that the mid-IR emission originates from compact regions and displays impulsive behavior.…”

Section: Introductionmentioning

confidence: 99%

A solar flare driven by thermal conduction observed in mid-infrared

López

Castro

Mandrini

et al. 2022

A&A

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Context. The mid-infrared (mid-IR) range has been mostly unexplored for the investigation of solar flares. It is only recently that new mid-IR flare observations have begun opening a new window into the response and evolution of the solar chromosphere. These new observations have been mostly performed by the AR30T and BR30T telescopes that are operating in Argentina and Brazil, respectively. Aims. We present the analysis of SOL2019-05-15T19:24, a GOES class C2.0 solar flare observed at 30 THz (10 μm) by the ground-based telescope AR30T. Our aim is to characterize the evolution of the flaring atmosphere and the energy transport mechanism in the context of mid-IR emission. Methods. We performed a multi-wavelength analysis of the event by complementing the mid-IR data with diverse ground- and space-based data from the Solar Dynamics Observatory (SDO), the H-α Solar Telescope for Argentina, and the Expanded Owens Valley Solar Array (EOVSA). Our study includes the analysis of the magnetic field evolution of the flaring region and of the development of the flare. Results. The mid-IR images from AR30T show two bright and compact flare sources that are spatially associated with the flare kernels observed in ultraviolet (UV) by SDO. We confirm that the temporal association between mid-IR and UV fluxes previously reported for strong flares is also observed for this small flare. The EOVSA microwave data revealed flare spectra consistent with thermal free-free emission, which lead us to dismiss the existence of a significant number of non-thermal electrons. We thus consider thermal conduction as the primary mechanism responsible for energy transport. Our estimates for the thermal conduction energy and total radiated energy fall within the same order of magnitude, reinforcing our conclusions.

show abstract

Comparison of 30 THz impulsive burst time development to microwaves, Hα, EUV, and GOES soft X-rays

Cited by 5 publications

References 24 publications

The 6 September 2017 X9 Super Flare Observed From Submillimeter to Mid‐IR

The 6 September 2017 X9 Super Flare Observed From Submillimeter to Mid‐IR

A solar flare driven by thermal conduction observed in mid-infrared

A solar flare driven by thermal conduction observed in mid-infrared

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