Spectroscopic Observations of Magnetic Reconnection and Chromospheric Evaporation in an X-shaped Solar Flare

Li, Ying; Kelly, Madie; Ding, M. D.; Qiu, Jiong; Zhu, Xiaoshuai; Gan, Wenyan

doi:10.3847/1538-4357/aa89e4

Cited by 35 publications

(37 citation statements)

References 78 publications

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“…In an earlier study, used IRIS1330 Å slit-jaw images to follow the peculiar motions of an unusual X-shaped flare ribbon that suggest the presence of separatrices in the coronal field, with reconnection occurring all the way down to the Sun's surface. In the same event, Li et al (2017c) observed significantly broadened wings extending to 200 km s −1 in the spectra of the Si IV line close to the X-point, which they interpret as bidirectional flows produced by the separator reconnection. Such flows have rarely been observed by previous spectrometers.…”

Section: Magnetic Reconnection In Flaresmentioning

confidence: 79%

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: Magnetic Reconnection In Flaresmentioning

confidence: 79%

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

et al. 2021

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“…Figure 2b shows the line profiles of Mg ii k & h lines at sunspot umbra, and their line cores are not central reversals, but they are also non-Gaussian profiles. Therefore, the moment analysis method but not the single Gaussian fit is applied to estimate their Doppler velocities, line widths, and intensities (see detail in Li et al 2017).…”

Section: Spectroscopic Observations In the Mg II K Linementioning

confidence: 99%

Doppler shift oscillations of a sunspot detected by CYRA and IRIS

Yang

Bai

et al. 2020

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Context. The carbon monoxide (CO) molecular line at around 46655 Å in solar infrared spectra is often used to investigate the dynamic behavior of the cold heart of the solar atmosphere, i.e., sunspot oscillation, especially at the sunspot umbra. Aims. We investigated sunspot oscillation at Doppler velocities of the CO 7-6 R67 and 3-2 R14 lines that were measured by the Cryogenic Infrared Spectrograph (CYRA), as well as the line profile of Mg II k line that was detected by the Interface Region Imaging Spectrograph (IRIS). Methods. A single Gaussian function is applied to each CO line profile to extract the line shift, while the moment analysis method is used for the Mg II k line. Then the sunspot oscillation can be found in the time–distance image of Doppler velocities, and the quasi-periodicity at the sunspot umbra are determined from the wavelet power spectrum. Finally, the cross-correlation method is used to analyze the phase relation between different atmospheric levels. Results. At the sunspot umbra, a periodicity of roughly 5 min is detected at the Doppler velocity range of the CO 7-6 R67 line that formed in the photosphere, while a periodicity of around 3 min is discovered at the Doppler velocities of CO 3-2 R14 and Mg II k lines that formed in the upper photosphere or the temperature minimum region and the chromosphere. A time delay of about 2 min is measured between the strong CO 3-2 R14 line and the Mg II k line. Conclusions. Based on the spectroscopic observations from the CYRA and IRIS, the 3 min sunspot oscillation can be spatially resolved in the Doppler shifts. It may come from the upper photosphere or the temperature minimum region and then propagate to the chromosphere, which might be regarded as a propagating slow magnetoacoustic wave.

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“…利用更高空间分辨率的观测, Li等人 [73] 发现高温谱线Fe XXI(~10 MK)整体蓝移, 这与色球蒸发理论完全吻合. Li等人 [74] 在一个X形耀斑中发现了分界线重联 [31,75] 的光谱证据, 主要表现为过渡区Si IV谱线轮廓的红蓝翼展宽, 表明重联双向出流的速度高达150~200 km/s. (ⅰ) 耀斑电流片.…”

Section: 日冕中的振荡和波动unclassified