A Statistical Study of Solar White-Light Flares Observed by the White-Light Solar Telescope of the Lyman-Alpha Solar Telescope on the Advanced Space-Based Solar Observatory (ASO-S/LST/WST) at 360 nm

Jing, Zhichen; Li, Ying; Feng, Li; Li, Hui; Huang, Yu; Li, Youping; Su, Yang; Chen, Wei; Tian, Jun; Song, Dechao; Li, Jingwei; Xue, Jianchao; Zhao, Jie; Lu, Lei; Ying, Beili; Zhang, Ping; Su, Yingna; Zhang, Qingmin; Li, Dong; Ge, Yunyi; Li, Shuting; Li, Qiao; Li, Gen; Liu, Xiaofeng; Shi, Guanglu; Shan, Jiahui; Tian, Zhengyuan; Zhou, Yue; Gan, Weiqun

doi:10.1007/s11207-024-02251-9

Cited by 9 publications

(3 citation statements)

References 49 publications

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“…A study that calculates impulsiveness for other lines or bands may reveal that there exists an option for the development of the impulsiveness index that is more directly reflective of the traditionally defined impulsive phase. For example, a recent study by Jing et al (2024) reported on a sample of white-light flares between 2022 October and 2023 May observed in the Balmer continuum at 360 nm by the Advanced Space-based Solar Observatory. While the number of flares captured by this instrument (launched in 2022 October) is currently limited, this is an example of a promising option for determination of an impulsiveness index more useful in explaining the empirical relations between stellar flare impulsiveness and certain spectral quantities.…”

Section: Discussionmentioning

confidence: 99%

The Relationships among Solar Flare Impulsiveness, Energy Release, and Ribbon Development

Tamburri,

Kazachenko,

Kowalski

2024

ApJ

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We develop the impulsiveness index, a new classification system for solar flares using the Solar Dynamics Observatory/Extreme Ultraviolet Experiment 304 Å Sun-as-a-star light curves. Impulsiveness classifies events based on the duration and intensity of the initial high-energy deposition of energy into the chromosphere. In stellar flare U-band light curves, Kowalski et al. found that impulsiveness is related to quantities such as a proxy for the Balmer jump ratio. However, the lack of direct spatial resolution in stellar flares limits our ability to explain this phenomenon. We calculate impulsiveness for 1368 solar flares between 2010 April and 2014 May. We divide events into categories of low, mid, and high impulsiveness. We find, in a sample of 480 flares, that events with high maximum reconnection rate tend to also have high impulsiveness. For six case studies, we compare impulsiveness to magnetic shear, ribbon evolution, and energy release. We find that the end of the 304 Å light-curve rise phase in these case studies corresponds to the cessation of polarity inversion line (PIL)-parallel ribbon motion, while PIL-perpendicular motion persists afterward in most cases. The measured guide-field ratio for low- and mid-impulsiveness case-study flares decreases about an order of magnitude during the impulsive flare phase. Finally, we find that, in four of the six case studies, flares with higher, more persistent shear tend to have low impulsiveness. Our study suggests that impulsiveness may be related to other properties of the impulsive phase, though more work is needed to verify this relationship and apply our findings to stellar flare physics.

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Section: Discussionmentioning

confidence: 99%

The Relationships among Solar Flare Impulsiveness, Energy Release, and Ribbon Development

Tamburri,

Kazachenko,

Kowalski

2024

ApJ

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“…The WST can provide full-disk images in the continuum at 3600 ± 20 Å. The pixel size of the images is ≈ 0.5 while the spatial resolution is about 4 (Jing et al, 2024). The cadence is two minutes in a routine mode.…”

Section: Datamentioning

confidence: 99%

Spectral and Imaging Observations of a C2.3 White-Light Flare from the Advanced Space-Based Solar Observatory (ASO-S) and the Chinese H$\alpha $ Solar Explorer (CHASE)

Li,

et al. 2024

Sol Phys

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Solar white-light flares are characterized by an enhancement in the optical continuum, which are usually large flares (X- and M-class flares). Here, we report a small C2.3 white-light flare (SOL2022-12-20T04:10) observed by the Advanced Space-based Solar Observatory and the Chinese H$\alpha $ α Solar Explorer (CHASE). This flare exhibits an increase of ≈ 6.4% in the photospheric Fe i line at 6569.2 Å and ≈ 3.2% in the nearby continuum. The continuum at 3600 Å also shows an enhancement of ≈ 4.7%. The white-light bright kernels are mainly located at the flare ribbons and co-spatial with nonthermal hard X-ray sources, which implies that the enhanced white-light emissions are related to nonthermal electron-beam heating. At the bright kernels, the Fe i line displays an absorption profile that has a good Gaussian shape, with a redshift up to ≈ 1.7 km s−1, while the H$\alpha $ α line shows an emission profile having a central reversal. The H$\alpha $ α line profile also shows a red or blue asymmetry caused by plasma flows with a velocity of several to tens of km s−1. It is interesting to find that the H$\alpha $ α asymmetry is opposite at the conjugate footpoints. It is also found that the CHASE continuum increase seems to be related to the change in the photospheric magnetic field. Our study provides comprehensive characteristics of a small white-light flare that help understand the energy release process of white-light flares.

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“…So far there are only several hundred solar WLFs reported in the literature based on ground-and space-based observations. Generally speaking, the larger flares, say, those of the X and M classes, are more likely identified as WLFs (e.g., Song & Tian 2018;Jing et al 2024).…”

Section: Introductionmentioning

confidence: 99%

The White-light Emissions in Two X-class Flares Observed by ASO-S and CHASE

Li,

Jing,

Song

et al. 2024

ApJL

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The white-light continuum emissions in solar flares (i.e., white-light flares) are usually observed on the solar disk but, in a few cases, off the limb. Here we present on-disk as well as off-limb continuum emissions at 3600 Å (in the Balmer continuum) in an X2.1 flare (SOL2023-03-03T17:52) and an X1.5 flare (SOL2023-08-07T20:46), respectively, observed by the White-light Solar Telescope on the Advanced Space-based Solar Observatory. These continuum emissions are seen at the ribbons for the X2.1 flare and on loops during the X1.5 event, in which the latter also appears in the decay phase. These emissions also show up in the pseudocontinuum images at Fe i λ6173 from the Helioseismic and Magnetic Imager on the Solar Dynamics Observatory. In addition, the ribbon sources in the X2.1 flare exhibit significant enhancements in the Fe i line at 6569.2 Å and the nearby continuum observed by the Chinese Hα Solar Explorer. It is found that the on-disk continuum emissions in the X2.1 flare are related to a nonthermal electron-beam heating either directly or indirectly, while the off-limb emissions in the X1.5 flare are associated with thermal plasma cooling or due to Thomson scattering. These comprehensive continuum observations provide good constraints on flare energy deposition models, which helps us to better understand the physical mechanism of white-light flares.

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A Statistical Study of Solar White-Light Flares Observed by the White-Light Solar Telescope of the Lyman-Alpha Solar Telescope on the Advanced Space-Based Solar Observatory (ASO-S/LST/WST) at 360 nm

Cited by 9 publications

References 49 publications

The Relationships among Solar Flare Impulsiveness, Energy Release, and Ribbon Development

The Relationships among Solar Flare Impulsiveness, Energy Release, and Ribbon Development

Spectral and Imaging Observations of a C2.3 White-Light Flare from the Advanced Space-Based Solar Observatory (ASO-S) and the Chinese H$\alpha $ Solar Explorer (CHASE)

The White-light Emissions in Two X-class Flares Observed by ASO-S and CHASE

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