The researchers found a possible mechanism for the formation of the solar light bridge and the disappearance of the penumbra

The researchers found a possible mechanism for the formation of the solar light bridge and the disappearance of the penumbra

Horizontal velocity around the sunspot derived from DAVE4VM. The background image shows the perpendicular magnetic field (positive field shown in white and negative field in black). Arrows represent horizontal velocity. The blue (red) arrows indicate that the vertical magnetic fields in pixels are positive (negative). The green lines show the outer limit of the sunspot (I = 0.9Iqs). credit: Astrophysical Journal (2023). DOI: 10.3847/1538-4357/aca667

Sunspots are the most prominent manifestation of solar magnetic field concentrations in the photosphere. A typical mature sunspot has a shade and is blonde. Light bridges (LBs) are the bright, ribbon-like features, the two ends of which connect between shadows and extend over a sunspot’s shadow.

The appearance of light bridges is usually an indication of sunspot Decay or fragmentation. development sunspots closely associated with solar eruptions, for example, Solar flaresAnd Coronal mass ejection, and capillary eruptions. However, until now, the mechanisms of sunspot formation and decay were not well understood.

Researchers led by Professor Yan Xiaoli of the Yunnan Observatories of the Chinese Academy of Sciences (CAS) and Li Qiaoling of the University of Yunnan analyzed the sunspot decay process in the NOAA 12680 active region on the Sun using stray light Calibrated data from the Solar Dynamics Observatory/Solar and Magnetic Imaging (SDO/HMI), and discussed the effect of light bridge on a degenerating sunspot.

The results are published in Astrophysical Journal On January 11th.

The researchers found that at the beginning of sunspot decay, some elongated dark structures were gradually separated from the shadow. The intensity, vertical field strength, and magnetic inclination of these dark structures were between those of shadow and shadow. With the formation of a light bridge, the total magnetic flux of the entire penumbra region gradually decreased, and the part of the darkness on one side of the light bridge quickly disappeared.

In addition, after the emergence of an outward movement of a magnetic flux along the photobridge, the decay rate of the area and magnetic flux of the semi-filled segment quickly die off. These results indicate that the rapid decay of the narrow segment was related to the light bridge.

“The dark structure in the penumbra and the formation of the light bridge may be the result of the diffuse magnetic flux from the shadow, which may accelerate the decomposition of sunspots,” Professor Yan said.

more information:
Qiaoling Li et al, Rapid decay of the Penumbral segment associated with a strong light bridge in NOAA active region 12680, Astrophysical Journal (2023). DOI: 10.3847/1538-4357/aca667

the quote: Researchers find possible mechanism for solar light bridge formation and penumbra disappearance (2023, January 18) Retrieved January 19, 2023 from

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