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

Abstract

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.

Formation and material supply of an active-region filament associated with newly emerging flux

“…It is widely accepted that the material of the filaments or prominences should originate from the low atmosphere (chromosphere) (Pikel'Ner 1971;Zirker et al 1994;Liu et al 2005;Yang et al 2016;Wang et al 2018). In this paper, we also confirm that the mass of the filament was extracted from the low atmosphere instead of the corona.…”

“…Furthermore, the only few observation evidences could be captured to supported to the this models ). On the other hand, many observations are more likely to support the injection models which rely on magnetic reconnection in the low atmosphere to propel cool plasma to typical filament height (Wang 1999;Liu et al 2005;Zou et al 2017;Wang et al 2018). In this paper, we supplied a observational evidence that the filament material can be supplied by a series of jets related to the new emerging magnetic field, which again verify the injection model.…”

“…This filamentary structure with high twisted structures eventually evolved as the filament, while the another filamentary structure could not maintain stable as the ejected plasma falls down the chromosphere. Wang et al (2018) also suggested that the ejected plasma is more earlier to be captured by the high twisted structures magnetic field and more stable to remain in the filament. In addiction, previous studies also showed that high twisted structures could be found in the filament during the activity or eruption of solar filaments (Cheng et al 2014b;Yang et al 2014;Bi et al 2015;Xue et al 2016;Jiang et al 2016).…”

Stereoscopic Observations of an Erupting Mini-filament-driven Two-sided-loop Jet and the Applications for Diagnosing a Filament Magnetic Field

“…Previous studies have proposed various models for explaining the mass formation of filaments, such as the injection model (Wang 1999), levitation model (Rust & Kumar 1994), and the evaporation-condensation model (Engvold & Jensen 1977;Xia et al 2011Xia et al , 2012Xia et al , 2014. Liu et al (2005) found that the cool filament mass can be provided the chromospheric jets from one end along the filament main axis (see also Wang et al (2018)), in which the authors did not explain how the cool jet mass injected into the filament channel. The event studied in the present paper clearly exhibited that the two-sided loop jet injected mass into the overlying LF from the below by the magnetic reconnection between the jet and the magnetic field of the filament's cavity.…”

Can an injection model replenish filaments in a weak magnetic environment?

“…In the observation of Liu et al (2005), they suggested that erupting Hα surges may directly link to the replenishment of filament materials. Furthermore, more and more observational evidences support this scenario (Zou et al 2016(Zou et al , 2017Wang et al 2018). All of these works indicate that a chromospheric eruption can be a source origin of filament replenishment.…”