Formation of Pores Associated With the Inflow of Moving Magnetic Features

Li, Xiaobo; Yang, Zhiliang; Zhang, Hongqi

doi:10.1088/0004-637x/807/2/160

Cited by 2 publications

(1 citation statement)

References 32 publications

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“…They cancel and merge like other magnetic features on the Sun. Like elementary bipoles, a sufficient collection of moving magnetic features of the same polarity can merge to form small sunspots (Li et al, 2015). Such mergers confirm that these sunspots are not different than small sunspots formed by clusters of elementary bipoles.…”

Section: Similarities Between Moving Magnetic Features and Elementarymentioning

confidence: 71%

Observational Evidence of Shallow Origins for the Magnetic Fields of Solar Cycles

Martin

2018

Front. Astron. Space Sci.

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Observational evidence for the origin of active region magnetic fields has been sought from published information on extended solar cycles, statistical distributions of active regions and ephemeral regions, helioseismology results, positional relationships to supergranules, and fine-scale magnetic structure of active regions and their sunspots during their growth. Statistical distributions of areas of ephemeral and active regions blend together to reveal a single power law. The shape of the size distribution in latitude of all active regions is independent of time during the solar cycle, yielding further evidence that active regions of all sizes belong to the same population. Elementary bipoles, identified also by other names, appear to be the building blocks of active regions; sunspots form from elementary bipoles and are therefore deduced to develop from the photosphere downward, consistent with helioseismic detection of downflows to 3-4 Mm below sunspots as well as long-observed downflows from chromospheric/coronal arch filaments into sunspots from their earliest appearance. Time-distance helioseismology has been effective in revealing flows related to sunspots to depths of 20 Mm. Ring diagram analysis shows a statistically significant preference for upflows to precede major active region emergence and downflows after flux emergence but both are often observed together or not detected. From deep-focus helioseismic techniques for seeking magnetic flux below the photosphere prior major active regions, there is evidence of acoustic travel-time perturbation signatures rising in the limited range of depths of 42-75 Mm but these have not been verified or found at more shallow depths by helioseismic holographic techniques. The development of active regions from clusters of elementary bipoles appears to be the same irrespective of how much flux an active region eventually develops. This property would be consistent with the magnetic fields of large active regions being generated in the same way and close the same depth as small active regions in a shallow zone below the photosphere. All evidence considered together, understanding the origins of the magnetic fields of solar cycles boils down to learning how and where elementary bipoles are generated beneath the photosphere.

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Section: Similarities Between Moving Magnetic Features and Elementarymentioning

confidence: 71%

Observational Evidence of Shallow Origins for the Magnetic Fields of Solar Cycles

Martin

2018

Front. Astron. Space Sci.

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Filamentary Structures Formation around a Magnetic Pore Using High-resolution Observations of the Goode Solar Telescope

Zhao,

Yu,

Zhu

et al. 2024

ApJ

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With the aid of high-resolution spatial and temporal observations from the Goode Solar Telescope, we present an investigation of the emergence, coalescence, and submergence of a moving magnetic feature (MMF) in the region surrounding a magnetic pore located at the periphery of a large sunspot. The results show that the MMF has a magnetic field strength greater than 500 G and is dominated by the horizontal magnetic component. We observe upflow at the inner part and downflow at the outer part, indicating a pattern of Evershed flow. The MMF emergence is accompanied by the expansion of a granule, which has several striations inside just like the twisted features found in the penumbra filament. Our analysis shows that although these striations have different properties of magnetic field and kinematics during the expansion of the granule, the overall magnetic and dynamic properties of the MMF remain stable. We find that the region where the MMF emerges and submerges becomes more penumbra-like, i.e., adjacent positive and negative values of elongated magnetic features that are parallel to each other, while the optical penumbra-like features are not apparent at the same time. Our work indicates that the dynamics of the MMF near the magnetic pore is important for the development of filamentary structure. The magnetic configuration produced by an MMF together with the elongation of a granule could thus be key to understand the formation of penumbra filaments.

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Formation of Pores Associated With the Inflow of Moving Magnetic Features

Cited by 2 publications

References 32 publications

Observational Evidence of Shallow Origins for the Magnetic Fields of Solar Cycles

Observational Evidence of Shallow Origins for the Magnetic Fields of Solar Cycles

Filamentary Structures Formation around a Magnetic Pore Using High-resolution Observations of the Goode Solar Telescope

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