Explosive Chromospheric Evaporation Driven by Nonthermal Electrons around One Footpoint of a Solar Flare Loop

Li, D.; Ning, Zongjun; Yu, Haitao; Zhang, Q. M.

doi:10.3847/2041-8213/aa71b0

Cited by 34 publications

(45 citation statements)

References 51 publications

(95 reference statements)

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“…Several recent studies have provided support for electron beams being the main carrier of energy from the flare site to the ribbons (e.g. Tian et al, 2015;Li, Ning, and Zhang, 2015b;Sadykov et al, 2015;Polito et al, 2016b;Brosius, Daw, and Inglis, 2016;Li et al, 2017b;Reep et al, 2019). These studies were based on correlations between evaporation/condensation flows observed with IRIS and hard X-ray and radio fluxes (assumed to be associated with non-thermal electrons), as well as comparison with hydrodynamic models.…”

Section: Iris Lines As Diagnostics Of Flare Heating Mechanismsmentioning

confidence: 99%

A New View of the Solar Interface Region from the Interface Region Imaging Spectrograph (IRIS)

et al. 2021

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The Interface Region Imaging Spectrograph (IRIS) has been obtaining near- and far-ultraviolet images and spectra of the solar atmosphere since July 2013. IRIS is the highest resolution observatory to provide seamless coverage of spectra and images from the photosphere into the low corona. The unique combination of near- and far-ultraviolet spectra and images at sub-arcsecond resolution and high cadence allows the tracing of mass and energy through the critical interface between the surface and the corona or solar wind. IRIS has enabled research into the fundamental physical processes thought to play a role in the low solar atmosphere such as ion–neutral interactions, magnetic reconnection, the generation, propagation, and dissipation of waves, the acceleration of non-thermal particles, and various small-scale instabilities. IRIS has provided insights into a wide range of phenomena including the discovery of non-thermal particles in coronal nano-flares, the formation and impact of spicules and other jets, resonant absorption and dissipation of Alfvénic waves, energy release and jet-like dynamics associated with braiding of magnetic-field lines, the role of turbulence and the tearing-mode instability in reconnection, the contribution of waves, turbulence, and non-thermal particles in the energy deposition during flares and smaller-scale events such as UV bursts, and the role of flux ropes and various other mechanisms in triggering and driving CMEs. IRIS observations have also been used to elucidate the physical mechanisms driving the solar irradiance that impacts Earth’s upper atmosphere, and the connections between solar and stellar physics. Advances in numerical modeling, inversion codes, and machine-learning techniques have played a key role. With the advent of exciting new instrumentation both on the ground, e.g. the Daniel K. Inouye Solar Telescope (DKIST) and the Atacama Large Millimeter/submillimeter Array (ALMA), and space-based, e.g. the Parker Solar Probe and the Solar Orbiter, we aim to review new insights based on IRIS observations or related modeling, and highlight some of the outstanding challenges.

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Section: Iris Lines As Diagnostics Of Flare Heating Mechanismsmentioning

confidence: 99%

A New View of the Solar Interface Region from the Interface Region Imaging Spectrograph (IRIS)

et al. 2021

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“…In the HXR images, the HXR emissions often appear firstly at two footpoint sources, and then rise upward along their loop legs, subsequently merge into a single source at the loop-top region (Liu et al 2006(Liu et al , 2008Ning & Cao 2010, 2011Ning 2011). The same observational features can also be seen in the high-temperature EUV images, for instance, the drastic mass motions from the double footpoints along the hot flare loop to the loop top (Li et al 2017;Zhang et al 2019). This is regarded as the HXR/EUV signature of chromospheric evaporation (e.g., Liu et al 2006;Ning 2011;Zhang et al 2019).…”

Section: Introductionmentioning

confidence: 71%

“…While the cool chromospheric or transition region lines could exhibit low-velocity red shifts due to the slow downward mass motions, or may show blue shifts without associated clear downflows. The former one is often regarded as 'explosive evaporation' (Milligan et al 2006a;Zhang et al 2016b;Brosius & Inglis 2017;Li et al 2017), and the latter one is referred as 'gentle evaporation' (Milligan et al 2006b;Sadykov et al 2015;Li et al 2019). These two types of chromospheric evaporation are often depending on the heating energy of electron beams, for instance, a critical threshold of about 10 10 erg s −1 cm −2 (e.g., Fisher et al 1985;Kleint et al 2016;Sadykov et al 2019).…”

Section: Introductionmentioning

confidence: 99%

“…Chromospheric evaporation has been detected in a large number of solar flares (e.g., Ding et al 1996;Li & Ding 2004;Falewicz et al 2009;Raftery et al 2009;Chen & Ding 2010;Veronig et al 2010;Li & Ding 2011;Brosius 2013;Young et al 2015;Brosius & Inglis 2018;Tian & Chen 2018), largely benefiting from the spectroscopic observations, such as, the Bragg Crystal Spectrometer on board Yohkoh, the Coronal Diagnostic Spectrometer aboard the Solar and Heliospheric Observatory, the Extreme-ultraviolet Imaging Spectrometer experiment aboard Hinode, the Interface Region Imaging Spectrograph (IRIS), et cetera. They can be detected in the pre-flare phase (Brosius & Holman 2010;Li et al 2018), impulsive phase (Graham & Cauzzi 2015;Li et al 2017;Sadykov et al 2019) and gradual/decay phase of solar flares (Czaykowska et al 1999;Li et al 2012;Brannon 2016). The chromospheric evaporation could be explained by the electron driven (Tian et al 2015;Warren et al 2016;Lee et al 2017) or the thermal conduction driven (Czaykowska et al 2001;Battaglia et al 2015;Ashfield & Longcope 2021), as well as the dissipation of Alvén waves (Fletcher & Hudson 2008;Reep & Russell 2016).…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous Observations of Chromospheric Evaporation and Condensation during a C-class Flare

Li,

Hong,

Ning

2021

Preprint

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We explored simultaneous observations of chromospheric evaporation and condensation during the impulsive phase of a C6.7 flare on 9 May 2019. The solar flare was simultaneously observed by multiple instruments, i.e., the New Vacuum Solar Telescope (NVST), the Interface Region Imaging Spectrograph, the Atmospheric Imaging Assembly (AIA), the Fermi, the Mingantu Spectral Radioheliograph, and the Nobeyama Radio Polarimeters. Using the single Gaussian fitting and the moment analysis technique, redshifted velocities at slow speeds of 15−19 km s −1 are found in the cool lines of C II and Si IV at one flare footpoint location. Red shifts are also seen in the Hα line-of-sight (LOS) velocity image measured by the NVST at double footpoints. Those red shifts with slow speeds can be regarded as the low-velocity downflows driven by the chromospheric condensation. Meanwhile, the converging motions from double footpoints to the loop top are found in the high-temperature EUV images, such as AIA 131 Å, 94 Å, and 335 Å. Their apparent speeds are estimated to be roughly 126−210 km s −1 , which could be regarded as the high-velocity upflows caused by the chromospheric evaporation. The nonthermal energy flux is estimated to be about 5.7×10 10 erg s −1 cm −2 . The characteristic timescale is roughly equal to 1 minute. All these observational results suggest an explosive chromospheric evaporation during the flare impulsive phase. While a HXR/microwave pulse and a type III radio burst are found simultaneously, indicating that the explosive chromospheric evaporation is driven by the nonthermal electron.

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“…Com o avanço da tecnologia e aprimoramento dos instrumentos de observação solar, principalmente a bordo de satélites, como o Interface Region Imaging Spectrograph (IRIS) e o Extreme-ultraviolet Imaging Spectrometer (EIS), uma série de estudos do fenômeno da evaporação cromosférica tem sido realizada a partir de dados de linhas espectrais no extremo ultravioleta e deslocamento Doppler. Entre esses trabalhos, podem ser citados, Li et al (2019); Li et al, (2015); Gömöry et al (2016); Li et al (2017a); Li et al, (2017b); Brosius e Inglis (2017); Lee et al (2017) e Gupta, Sarkar e Tripathi (2018); Sadykov et al (2019). A evaporação cromosférica também tem sido estudada a partir de imagens e dados do arranjo de telescópios Atmospheric Imaging Assembly (AIA), abordo do Solar Dynamics Observatory (SDO) (ZHANG et al, 2019).…”

Section: Introductionunclassified

Análise De Emissões Solares Métricas Com Lenta Taxa De Deriva Em Frequência Associadas À Evaporação Cromosférica

Korol

Fernandes

2021

RevistaUnivap

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Por meio de ferramentas computacionais desenvolvidas exclusivamente para extração e análise de dados solares obtidos pelos espectrógrafos da rede e-Callisto, foi realizada a análise de uma rádio-emissão solar registrada em ondas métricas (200 - 800 MHz), no dia 9 de agosto de 2011 (~08:32 UT). O espectro dinâmico da emissão solar gerado demonstra claramente a presença de uma lenta taxa de deriva de frequência, indício de uma frente de expansão ascendente de plasma aquecido, que caracteriza a evaporação cromosférica. A partir dos dados espectrais, uma função de ajuste para a relação entre frequência e tempo foi obtida, por meio de regressão linear e uma taxa de deriva em frequência de 1,14 MHz/s foi determinada. Então, a velocidade da frente de expansão de plasma aquecido foi estimada em 99,1 km/s (para a baixa coroa) e 369,6 km/s (para a alta coroa), adotando um modelo de densidade eletrônica para a região de emissão na coroa solar. Esses valores são comparáveis com resultados obtidos na literatura, confirmando que a rádio-emissão representa uma assinatura em ondas métricas do fenômeno da evaporação cromosférica. Por fim, ressalta-se que as ferramentas computacionais desenvolvidas se provam úteis para a extração e análise de dados de espectrógrafos da rede e-Callisto, e que por serem de código aberto, outros pesquisadores e desenvolvedores podem contribuir com alterações, correções, novas funcionalidades e até mesmo outros serviços e plataformas que as utilizem.

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Explosive Chromospheric Evaporation Driven by Nonthermal Electrons around One Footpoint of a Solar Flare Loop

Cited by 34 publications

References 51 publications

A New View of the Solar Interface Region from the Interface Region Imaging Spectrograph (IRIS)

A New View of the Solar Interface Region from the Interface Region Imaging Spectrograph (IRIS)

Simultaneous Observations of Chromospheric Evaporation and Condensation during a C-class Flare

Análise De Emissões Solares Métricas Com Lenta Taxa De Deriva Em Frequência Associadas À Evaporação Cromosférica

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