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arXiv · 2307.12641

Spectral Observations and Modeling of a Solar White-light Flare Observed by CHASE

De-Chao Song·Jun Tian·Y. Li·M. D. Ding·Yang Su·Sijie Yu·Jie Hong·Ye Qiu·Shihao Rao·Xiaofeng Liu·Qiao Li·Xingyao Chen·Chuan Li·Cheng Fang
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Abstract

The heating mechanisms of solar white-light flares remain unclear. We present an X1.0 white-light flare on 2022 October 2 (SOL2022-10-02T20:25) observed by the Chinese \ha\ Solar Explorer (CHASE) that provides two-dimensional spectra in the visible light for the full solar disk with a seeing-free condition. The flare shows a prominent enhancement of $\sim$40\% in the photospheric \fe\ line at 6569.2 \AA, and the nearby continuum also exhibits a maximum enhancement of $\sim$40\%. For the continuum near the \fe\ line at 6173 \AA\ from the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO), it is enhanced up to $\sim$20\%. At the white-light kernels, the \fe\ line at 6569.2 \AA\ has a symmetric Gaussian profile that is still in absorption and the H$\alpha$ line at 6562.8 \AA\ displays a very broad emission profile with a central reversal plus a red or blue asymmetry. The white-light kernels are co-spatial with the microwave footpoint sources observed by the Expanded Owens Valley Solar Array (EOVSA) and the time profile of the white-light emission matches that of the hard X-ray emission above 30 keV from the Gamma-ray Burst Monitor (GBM) on Fermi. These facts indicate that the white-light emission is qualitatively related to a nonthermal electron beam. We also perform a radiative hydrodynamic simulation with the electron beam parameters constrained by the hard X-ray observations from Fermi/GBM. The result reveals that the white-light enhancement cannot be well explained by a pure electron-beam heating together with its induced radiative backwarming but may need additional heating sources such as \alfven\ waves.

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De-Chao Song, Jun Tian, Y. Li, M. D. Ding, Yang Su, Sijie Yu, Jie Hong, Ye Qiu, Shihao Rao, Xiaofeng Liu, Qiao Li, Xingyao Chen, Chuan Li, Cheng Fang. 2023-07-24. Spectral Observations and Modeling of a Solar White-light Flare Observed by CHASE. https://doi.org/10.3847/2041-8213/ace18c

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