Large-amplitude Longitudinal Oscillations Triggered by the Merging of Two Solar Filaments: Observations and Magnetic Field Analysis

Luna, M.; Su, Yang; Schmieder, B.; Chandra, Ramesh; Kucera, T. A.

doi:10.3847/1538-4357/aa9713

Cited by 44 publications

(36 citation statements)

References 74 publications

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“…The damping time ranges from ∼62 to ∼96 minutes, with a mean value of 82.4 minutes. τ/P has a range of 1.2−1.8 and a mean value of 1.6, which is comparable to those of longitudinal oscillations on 2015 June 29 (Zhang et al 2017b), but smaller than most of the values (2−4) in literatures (e.g., Jing et al 2003;Vršnak et al 2007;Zhang et al 2012Zhang et al , 2017aLuna et al 2017). Observations in this study confirm our previous finding that oscillations with larger initial amplitudes tend to attenuate faster (τ ∼ v −0.3 0 ) ).…”

Section: Filament Oscillationssupporting

confidence: 52%

Longitudinal filament oscillations enhanced by two C-class flares

Zhang

Guo

Tam

et al. 2020

A&A

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Context. Large-amplitude, longitudinal filament oscillations triggered by solar flares have been well established. However, filament oscillations enhanced by flares have never been reported. Aims. In this paper, we report the multiwavelength observations of a very long filament in active region (AR) 11112 on 2010 October 18. The filament was composed of two parts, the eastern part (EP) and western part (WP). We focus on longitudinal oscillations of the EP, which were enhanced by two homologous C-class flares in the same AR. Methods. The filament was observed in Hα wavelength by the GONG and in extreme ultra-violet (EUV) wavelengths by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). Line-of-sight magnetograms were provided by the Helioseismic and Magnetic Imager (HMI) on board SDO. The global three-dimensional (3D) magnetic fields were obtained using the potential field source surface modeling. Soft X-ray light curves of the two flares were recorded by the GOES spacecraft. Whitelight images of the corona were observed by the LASCO/C2 coronagraph on board SOHO. To reproduce part of the observations, we perform one-dimensional, hydrodynamic numerical simulations using the MPI-AMRVAC code.Results. The C1.3 flare was confined without a CME. Both EP and WP of the filament were slightly disturbed and survived the flare. After 5 hrs, eruption of the WP generated a C2.6 flare and a narrow, jet-like CME. Three oscillating threads (thd a , thd b , thd c ) are obviously identified in the EP and their oscillations are naturally divided into three phases by the two flares. The initial amplitude ranges from 1.6 to 30 Mm with a mean value of ∼14 Mm. The period ranges from 34 to 73 minutes with a mean value of ∼53 minutes. The curvature radii of the magnetic dips are estimated to be 29 to 133 Mm with a mean value of ∼74 Mm. The damping times ranges from ∼62 to ∼96 minutes with a mean value of ∼82 minutes. The value of τ/P is between 1.2 and 1.8. For thd a in the EP, the amplitudes were enhanced by the two flares from 6.1 Mm to 6.8 Mm after the C1.3 flare and further to 21.4 Mm after the C2.6 flare. The period variation as a result of perturbation from the flares was within 20%. The attenuation became faster after the C2.6 flare. Conclusions. To the best of our knowledge, this is the first report of large-amplitude, longitudinal filament oscillations enhanced by flares. Numerical simulations reproduce the oscillations of thd a very well. The simulated amplitudes and periods are close to the observed values, while the damping time in the last phase is longer, implying additional mechanisms should be taken into account apart from radiative loss.

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Section: Filament Oscillationssupporting

confidence: 52%

Longitudinal filament oscillations enhanced by two C-class flares

Zhang

Guo

Tam

et al. 2020

A&A

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“…In addition, the magnetic field and the continuum were continuously observed with the HMI, Scherrer et al (2012); Schou et al (2012)). The evolution and the eruption of this long filament have been reported by Zheng et al (2017) and Luna et al (2017). On January 26 around 17:00 UT, the middle part of the filament started to rise ( Figure 1).…”

Section: Overviewmentioning

confidence: 54%

Horizontal photospheric flows trigger a filament eruption

Roudier

Schmieder

Filippov

et al. 2018

A&A

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Context. A large filament composed principally of two sections erupted sequentially in the southern hemisphere on January 26 2016. The central, thick part of the northern section was first lifted up and lead to the eruption of the full filament. This event was observed in Hα with the Global Oscillation Network Group (GONG) and Christian Latouche IMageur Solaire (CLIMSO), and in ultraviolet (UV) with the Atmospheric Imaging Assembly (AIA) imager on board the Solar Dynamic Observatory (SDO). Aims. The aim of the paper is to relate the photospheric motions below the filament and its environment to the eruption of the filament.Methods. An analysis of the photospheric motions using Solar Dynamic Observatory Helioseismic and Magnetic Imager (SDO/HMI) continuum images with the new version of the coherent structure tracking (CST) algorithm developed to track granules, as well as large-scale photospheric flows, has been performed. Following velocity vectors, corks migrate towards converging areas.Results. The supergranule pattern is clearly visible outside the filament channel but difficult to detect inside because the modulus of the vector velocity is reduced in the filament channel, mainly in the magnetized areas. The horizontal photospheric flows are strong on the west side of the filament channel and oriented towards the filament. The ends of the filament sections are found in areas of concentration of corks. Whirled flows are found locally around the feet. Conclusions. The strong horizontal flows with an opposite direction to the differential rotation create strong shear and convergence along the magnetic polarity inversion line (PIL) in the filament channel. The filament has been destabilized by the converging flows, which initiate an ascent of the middle section of the filament until the filament reaches the critical height of the torus instability inducing, consequently, the eruption. The n decay index indicated an altitude of 60 Mm for the critical height. It is conjectured that the convergence along the PIL is due to the large-scale size cells of convection that transport the magnetic field to their borders.

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“…Because the velocity amplitude is approximately V ∼ A/P , the region of large A and low P corresponds to very large V values where no events were found in our survey. Recently, we discovered an oscillation event with the largest velocity amplitude reported thus far (100 km s −1 ) and a displacement of more than 50 Mm Luna et al (2017), which would fit in the empty region of Figure 21(b).…”

Section: Displacement Amentioning

confidence: 82%

“…Subsequent seismological analyses of LALOs in prominences have derived the radius of curvature of dipped field lines supporting prominence threads, the minimum magnetic field strength, the energy injected by the triggering jet, and the mass accretion rate according to the thermal nonequilibrium model Bi et al 2014;Luna et al 2014Luna et al , 2016Zhang et al 2017b). Using the same seismological techniques, we determined the curvature radius of the magnetic field dips and the minimum field strength from the largest prominence oscillation ever reported in the literature; these results were validated by reconstructing the filament magnetic field from the photospheric field in combination with the flux-rope insertion method (Luna et al 2017).…”

Section: Introductionmentioning

confidence: 99%

GONG Catalog of Solar Filament Oscillations Near Solar Maximum

Luna

Karpen

Ballester

et al. 2018

ApJS

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We have catalogued 196 filament oscillations from the GONG Hα network data during several months near the maximum of solar cycle 24 (January -June 2014). Selected examples from the catalog are described in detail, along with our statistical analyses of all events. Oscillations were classified according to their velocity amplitude: 106 small-amplitude oscillations (SAOs), with velocities < 10 km s −1 , and 90 large-amplitude oscillations (LAOs), with velocities > 10 km s −1 . Both SAOs and LAOs are common, with one event of each class every two days on the visible side of the Sun. For nearly half of the events we identified their apparent trigger. The period distribution has a mean value of 58±15 min for both types of oscillations. The distribution of the damping time per period peaks at τ /P = 1.75 and 1.25 for SAOs and LAOs respectively. We confirmed that LAO damping rates depend nonlinearly on the oscillation velocity. The angle between the direction of motion and the filament spine has a distribution centered at 27 • for all filament types. This angle agrees with the observed direction of filament-channel magnetic fields, indicating that most of the catalogued events are longitudinal (i.e., undergo field-aligned motions). We applied seismology to determine the average radius of curvature in the magnetic dips, R ≈ 89 Mm, and the average minimum magnetic-field strength, B ≈ 16 G. The catalog is available to the community online, and is intended to be expanded to cover at least 1 solar cycle.

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Large-amplitude Longitudinal Oscillations Triggered by the Merging of Two Solar Filaments: Observations and Magnetic Field Analysis

Cited by 44 publications

References 74 publications

Longitudinal filament oscillations enhanced by two C-class flares

Longitudinal filament oscillations enhanced by two C-class flares

Horizontal photospheric flows trigger a filament eruption

GONG Catalog of Solar Filament Oscillations Near Solar Maximum

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