Triggered Magnetic Energy Release in Solar Flares

Hu, Youqiu; Li, X.; Ai, G. X.

doi:10.1086/176270

Cited by 8 publications

(6 citation statements)

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“…Two-dimensional (e.g. De Young et al 1971Winglee et al 1991;Hu et al 1995;Forbes et al 1995;Yokoyama & Shibata 1998;Zhang et al 2006) and three-dimensional simulations (e.g. Wu et al 1992;Magara et al 1999;Miyagoshi et al 2004;Aulanier et al 2006;Birn et al 2006) are widely used to study the magnetic reconnection in process of flares and CMEs.…”

Section: Introductionmentioning

confidence: 99%

ON THE BRIGHTENING PROPAGATION OF POST-FLARE LOOPS OBSERVED BYTRACE

Zhang

2008

ApJ

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Examining flare data observed by TRACE satellite from May 1998 to December 2006, we choose 190 (151 M-class and 39 X-class) flare events which display post-flare loops (PFLs), observed by 171Å and 195Å wavelengths. 124 of the 190 events exhibit flare ribbons (FRs), observed by 1600Å images. We investigate the propagation of the brightening of these PFLs along the neutral lines and the separation of the FRs perpendicular to the neutral lines. Observations indicate that the footpoints of the initial brightening PFLs are always associated with the change of the photospheric magnetic fields. In most of the cases, the length of the FRs ranges from 20 Mm to 170 Mm. The propagating duration of the brightening is from 10 minutes to 60 minutes, and from 10 minutes to 70 minutes for the separating duration of the FRs. The velocities of the propagation and the separation range from 3 km s −1 to 39 km s −1 and 3 km s −1 to 15 km s −1 , respectively. Both of the propagating velocities and the separating velocities are associated with the flare strength and the length of the FRs. It appears that the propagation and the separation are dynamically coupled, that is the greater the propagating velocity is, the faster the separation is. Furthermore, a greater propagating velocity corresponds to a greater deceleration (or acceleration). These PFLs display three types of propagating patterns. Type I propagation, which possesses about half of all the events, is that the brightening begins at the middle part of a set of PFLs, and propagates bi-directionally towards its both ends. Type II, possessing 30%, is that the brightening firstly appears at one end of a set of PFLs, then propagates to the other end. The remnant belongs to Type III propagation which displays that the initial brightening takes place at two (or more than two) positions on two (or more than two) sets of PFLs, and each brightening propagates bi-directionally along the neutral line. These three types of propagating patterns can be explained by a three-dimensional magnetic reconnection model.

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Section: Introductionmentioning

confidence: 99%

ON THE BRIGHTENING PROPAGATION OF POST-FLARE LOOPS OBSERVED BYTRACE

Zhang

2008

ApJ

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“…In order to investigate the influence of flux feeding on flux rope systems, we must first construct a typical coronal flux rope system, and then realize the flux feeding process in simulations. Here we select a partially open bipolar field, with a negative and a positive surface magnetic charges located at the photosphere within −b < x < −a and a < x < b, respectively, as the background field, which can be obtained by the complex variable method (e.g., Hu et al 1995;Zhang et al 2017a). The background magnetic field can be cast in the complex variable form…”

Section: Discussionmentioning

confidence: 99%

Eruption of Solar Magnetic Flux Ropes Caused by Flux Feeding

Zhang¹,

Wang²,

Liu³

et al. 2020

ApJL

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Large-scale solar eruptions are believed to have a magnetic flux rope as the core structure. However, it remains elusive as to how the flux rope builds up and what triggers its eruption. Recent observations found that a prominence erupted following multiple episodes of "flux feeding". During each episode, a chromospheric fibril rose and merged with the prominence lying above. In this letter, we carried out 2.5-dimensional magnetohydrodynamic (MHD) numerical simulations to investigate whether the flux-feeding mechanism can explain such an eruption. The simulations demonstrate that the discrete emergence of small flux ropes can initiate eruptions by feeding axial flux into the preexistent flux rope until its total axial flux reaches a critical value. The onset of the eruption is dominated by an ideal MHD process. Our simulation results corroborate that the flux feeding is a viable mechanism to cause the eruption of solar magnetic flux ropes.

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“…Here we select a partially open bipolar field as the background field, in which a negative and a positive surface magnetic charge located at the photosphere within −b < x < −a and a < x < b, respectively. The background field could then be obtained by the complex variable method (e.g., Hu et al 1995;Zhang et al 2017). The background magnetic field can be cast in the complex variable form…”

Section: Appendix A: Basic Equations and Initial Preparationsmentioning

confidence: 99%

How flux feeding causes eruptions of solar magnetic flux ropes with the hyperbolic flux tube configuration?

Zhang,

Liu,

Wang

et al. 2021

Preprint

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Coronal magnetic flux ropes are generally considered to be the core structure of large-scale solar eruptions. Recent observations found that solar eruptions could be initiated by a sequence of "flux feeding," during which chromospheric fibrils rise upward from below, and merge with a pre-existing prominence. Further theoretical study has confirmed that the flux feeding mechanism is efficient in causing the eruption of flux ropes that are wrapped by bald patch separatrix surfaces. But it is unclear how flux feeding influences coronal flux ropes that are wrapped by hyperbolic flux tubes (HFT), and whether it is able to cause the flux-rope eruption. In this paper, we use a 2.5-dimensional magnetohydrodynamic model to simulate the flux feeding processes in HFT configurations. It is found that flux feeding injects axial magnetic flux into the flux rope, whereas the poloidal flux of the rope is reduced after flux feeding. Flux feeding is able to cause the flux rope to erupt, provided that the injected axial flux is large enough so that the critical axial flux of the rope is reached. Otherwise, the flux rope system evolves to a stable equilibrium state after flux feeding, which might be even farther away from the onset of the eruption, indicating that flux feeding could stabilize the rope system with the HFT configuration in this circumstance.

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Triggered Magnetic Energy Release in Solar Flares

Cited by 8 publications

References 0 publications

ON THE BRIGHTENING PROPAGATION OF POST-FLARE LOOPS OBSERVED BYTRACE

ON THE BRIGHTENING PROPAGATION OF POST-FLARE LOOPS OBSERVED BYTRACE

Eruption of Solar Magnetic Flux Ropes Caused by Flux Feeding

How flux feeding causes eruptions of solar magnetic flux ropes with the hyperbolic flux tube configuration?

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