Very long-periodic pulsations detected simultaneously in a white-light flare and sunspot penumbra
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arXiv
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| Format: | Preprint |
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2024
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| _version_ | 1866913483821416448 |
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| author | Li, Dong Wang, Jincheng Huang, Yu |
| author_facet | Li, Dong Wang, Jincheng Huang, Yu |
| contents | We investigate the origin of very long-periodic pulsations (VLPs) in the white-light emission of an X6.4 flare on 2024 February 22 (SOL2024-02-22T22:08), which occurred at the edge of a sunspot group. The flare white-light fluxes reveal four successive and repetitive pulsations, which are simultaneously measured by the Helioseismic and Magnetic Imager and the White-light Solar Telescope. A quasi-period of 8.6$^{+1.5}_{-1.9}$ minutes, determined by the Morlet wavelet transform, is detected in the visible continuum channel. The modulation depth, which is defined as the ratio between the oscillatory amplitude and its long-term trend, is smaller than 0.1%, implying that the QPP feature is a weak wave process. Imaging observations show that the X6.4 flare occurs near a sunspot group. Moreover, the white-light brightening is located in sunspot penumbra, and a similar quasi-period of about 8.5$^{+1.6}_{-1.8}$ minutes is identified in one penumbral location of the nearest sunspot. The map of Fourier power distribution suggests that a similar periodicity is universally existing in most parts of the penumbra that is close to the penumbral-photospheric boundary. Our observations support the scenario of that the white-light QPP is probably modulated by the slow-mode magnetoacoustic gravity wave leaking from the sunspot penumbra. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2408_15706 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Very long-periodic pulsations detected simultaneously in a white-light flare and sunspot penumbra Li, Dong Wang, Jincheng Huang, Yu Solar and Stellar Astrophysics We investigate the origin of very long-periodic pulsations (VLPs) in the white-light emission of an X6.4 flare on 2024 February 22 (SOL2024-02-22T22:08), which occurred at the edge of a sunspot group. The flare white-light fluxes reveal four successive and repetitive pulsations, which are simultaneously measured by the Helioseismic and Magnetic Imager and the White-light Solar Telescope. A quasi-period of 8.6$^{+1.5}_{-1.9}$ minutes, determined by the Morlet wavelet transform, is detected in the visible continuum channel. The modulation depth, which is defined as the ratio between the oscillatory amplitude and its long-term trend, is smaller than 0.1%, implying that the QPP feature is a weak wave process. Imaging observations show that the X6.4 flare occurs near a sunspot group. Moreover, the white-light brightening is located in sunspot penumbra, and a similar quasi-period of about 8.5$^{+1.6}_{-1.8}$ minutes is identified in one penumbral location of the nearest sunspot. The map of Fourier power distribution suggests that a similar periodicity is universally existing in most parts of the penumbra that is close to the penumbral-photospheric boundary. Our observations support the scenario of that the white-light QPP is probably modulated by the slow-mode magnetoacoustic gravity wave leaking from the sunspot penumbra. |
| title | Very long-periodic pulsations detected simultaneously in a white-light flare and sunspot penumbra |
| topic | Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2408.15706 |