The Formation of a Small-Scale Filament After Flux Emergence on the Quiet Sun

Chen, Hechao; Yang, Jiayan; Yang, Bo; Ji, Kaifan; Bi, Yong

doi:10.1007/s11207-018-1311-8

Cited by 20 publications

(15 citation statements)

References 73 publications

(104 reference statements)

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“…The minifilament was associated with flare-like brightenings near its apparent footpoints, another common feature reported in literature (e.g., Ren et al 2008;Hong et al 2011;Chen et al 2018b). Some of these were seen in EUV, more brightly in 304 Å, before the start of the slow expansion.…”

Section: Discussionsupporting

confidence: 57%

“…Another pertinent example is the finding that the quiet-Sun magnetic fields of the network obey a fundamental free energy-magnetic helicity relationship (Tziotziou et al 2014), similarly to active regions, although in the quiet-Sun magnetic helicity builds mainly because of the action of the shuffling motions on smallscale magnetic fields (Tziotziou et al 2015). Chen et al (2018b) attributed the formation of a minifilament to such motions, resulting to helicity injection after emergence of small-scale magnetic flux. The persistent converging motions of the magnetic footpoints of the region also seem to be involved in the formation and destabilization of the minifilament presented here.…”

Section: Discussionmentioning

confidence: 99%

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High-resolution spectroscopy of an erupting minifilament and its impact on the nearby chromosphere

Kontogiannis,

Dineva,

Diercke

et al. 2020

Preprint

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We study the evolution of a mini-filament eruption in a quiet region at the center of the solar disk and its impact on the ambient atmosphere. We used high-spectral resolution imaging spectroscopy in Hα acquired by the echelle spectrograph of the Vacuum Tower Telescope (VTT), Tenerife, Spain, photospheric magnetic field observations from the Helioseismic Magnetic Imager (HMI), and UV/EUV imaging from the Atmospheric Imaging Assembly (AIA) of the Solar Dynamics Observatory (SDO). The Hα line profiles were noise-stripped using Principal Component Analysis (PCA) and then inverted to produce physical and cloud model parameter maps. The minifilament formed between small-scale, opposite-polarity magnetic features through a series of small reconnection events and it erupted within an hour after its appearance in Hα. Its development and eruption exhibited similarities with large-scale erupting filaments, indicating the action of common mechanisms. Its eruption took place in two phases, namely a slow rise and a fast expansion, and it produced a coronal dimming, before the minifilament disappeared. During its eruption we detected a complicated velocity pattern, indicative of a twisted, thread-like structure. Part of its material returned to the chromosphere producing observable effects on nearby low-lying magnetic structures. Cloud model analysis showed that the minifilament was initially similar to other chromospheric fine structures, in terms of optical depth, source function and Doppler width, but it resembled a large-scale filament on its course to eruption. High spectral resolution observations of the chromosphere can provide a wealth of information regarding the dynamics and properties of minifilaments and their interactions with the surrounding atmosphere.

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Section: Discussionsupporting

confidence: 57%

Section: Discussionmentioning

confidence: 99%

High-resolution spectroscopy of an erupting minifilament and its impact on the nearby chromosphere

Kontogiannis,

Dineva,

Diercke

et al. 2020

Preprint

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“…How cool and dense material is supplied to filaments embedded in the hot and tenuous corona remains an open question. On the one hand, many researchers investigated the formation of filament magnetic field structures and proposed two different efficient ways to form the magnetic field structures of filaments: surface effect (van Ballegooijen & Martens 1989;Martens & Zwaan 2001;Yan et al 2015Yang et al 2016;Wang et al 2017;Xue et al 2017;Chen et al 2018) and subsurface effect (Okamoto et al 2008(Okamoto et al , 2009Lites 2009;Lites et al 2010;MacTaggart & Hood 2010;. MacTaggart & Hood (2010) analyzed a set of MHD simulations on filament formation and supported the observation reported by Okamoto et al (2008Okamoto et al ( , 2009 that there was a flux rope emerging under the filament.…”

Section: Introductionmentioning

confidence: 71%

Formation of an Active Region Filament Driven By a Series of Jets

Wang

Yan

et al. 2018

ApJ

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We present a formation process of a filament in active region NOAA 12574 during the period from 2016 August 11 to 12. Combining the observations of GONG Hα, Hida spectrum and SDO/AIA 304 A, the formation process of the filament is studied. It is found that cool material (T ∼ 10 4 K) is ejected by a series of jets originating from the western foot-point of the filament. Simultaneously, the magnetic flux emerged from the photosphere in the vicinity of the western foot-point of the filament. These observations suggest that cool material in the low atmosphere can be directly injected into the upper atmosphere and the jets are triggered by the magnetic reconnection between pre-existing magnetic fields and new emerging magnetic fields. Detailed study of a jet at 18:02 UT on August 11 with GST/BBSO TiO observations reveals that some dark threads appeared in the vicinity of the western foot-point after the jet and the projection velocity of plasma along the filament axis was about 162.6±5.4 km/s. Using with DST/Hida observations, we find that the injected plasma by a jet at 00:42 UT on August 12 was rotating. Therefore, we conclude that the jets not only supplied the material for the filament, but also injected the helicity into the filament simultaneously. Comparing the quantity of mass injection by the jets with the mass of the filament, we conclude that the estimated mass loading by the jets is sufficient to account for the mass in the filament.

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“…The observational sunspots and active regions (ARs) are thought to be born of the emerging magnetic flux, which is the concentration of the magnetic fields (van Driel-Gesztelyi & Green 2015). On the other hand, many solar activities are triggered by newly emerging magnetic flux, such as coronal mass ejections (CMEs), flares, formations or eruptions of the filaments, jets, and small-scale bursts (e.g., Feynman & Martin 1995;Chen & Shibata 2000;Isobe et al 2007;Yan et al 2017;Chen et al 2018;Wang et al 2018Wang et al , 2019Young et al 2018;Tian et al 2018). Such an emerging magnetic field not only plays a vital role in understanding active regions and sunspots, but it also has a great influence on many of the activities in taking place in the solar atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Naked emergence of an anti-Hale active region I. Overall evolution and magnetic properties

Wang,

Yan,

Kong

et al. 2021

Preprint

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Context.Aims. In order to understand the emergence of the active region, we investigate the emerging process and magnetic properties of a naked anti-Hale active region during the period between August 24 to 25, 2018. Methods. Using the data from Helioseismic and Magnetic Imager on board the Soar Dynamic Observatory and the New Vacuum Solar Telescope, we calculated different evolving parameters (such as pole separation, tilt angle) and magnetic parameters (such as vertical electric current, force-free parameter, relative magnetic helicity) during the emergence of the active region. With these calculated parameters and some reasonable assumptions, we use two different methods to estimate the twist of the active region. Results. The magnetic flux and pole separation continue increasing while the tilt angle exhibits a decreasing pattern during the emergence of the active region. The increase of the pole separation is mainly contributed as a result of the enhancement in the longitude direction. A power-law relationship between pole separation and total flux is found during the emergence of the active region. On the other hand, it is found that both the positive and negative electric currents increased equivalently and the average flux-weighted force-free parameter α remains almost consistently positive, on the order of ∼ 10 −8 m −1 . The relative magnetic helicity is mainly contributed by the shear term, while the relative magnetic helicity injection flux of the shear term changes its sign at the latter stage of the emergence. The twist number of the whole active region remains on the order of 10 −1 turns during the emergence of the active region. Conclusions. We find that the magnetic flux tube with low twist also could emerge into the solar atmosphere.

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The Formation of a Small-Scale Filament After Flux Emergence on the Quiet Sun

Cited by 20 publications

References 73 publications

High-resolution spectroscopy of an erupting minifilament and its impact on the nearby chromosphere

High-resolution spectroscopy of an erupting minifilament and its impact on the nearby chromosphere

Formation of an Active Region Filament Driven By a Series of Jets

Naked emergence of an anti-Hale active region I. Overall evolution and magnetic properties

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