scholarly journals Partial Eruption, Confinement, and Twist Buildup and Release of a Double-decker Filament

2021 ◽  
Vol 923 (2) ◽  
pp. 142
Author(s):  
Jialin Chen ◽  
Yingna Su ◽  
Rui Liu ◽  
Bernhard Kliem ◽  
Qingmin Zhang ◽  
...  
Keyword(s):  
Stable Equilibrium ◽  
Source Region ◽  
Flux Rope ◽  
Critical Height ◽  
Filament System ◽  
Field Modeling ◽  
Magnetic Field Modeling ◽  
Double Decker ◽  
Insertion Method ◽  
Magnetic Null

Abstract We investigate the failed partial eruption of a filament system in NOAA AR 12104 on 2014 July 5, using multiwavelength EUV, magnetogram, and Hα observations, as well as magnetic field modeling. The filament system consists of two almost co-spatial segments with different end points, both resembling a C shape. Following an ejection and a precursor flare related to flux cancellation, only the upper segment rises and then displays a prominent twisted structure, while rolling over toward its footpoints. The lower segment remains undisturbed, indicating that the system possesses a double-decker structure. The erupted segment ends up with a reverse-C shape, with material draining toward its footpoints, while losing its twist. Using the flux rope insertion method, we construct a model of the source region that qualitatively reproduces key elements of the observed evolution. At the eruption onset, the model consists of a flux rope atop a flux bundle with negligible twist, which is consistent with the observational interpretation that the filament possesses a double-decker structure. The flux rope reaches the critical height of the torus instability during its initial relaxation, while the lower flux bundle remains in stable equilibrium. The eruption terminates when the flux rope reaches a dome-shaped quasi-separatrix layer that is reminiscent of a magnetic fan surface, although no magnetic null is found. The flux rope is destroyed by reconnection with the confining overlying flux above the dome, transferring its twist in the process.

scholarly journals A Fundamental Mechanism of Solar Eruption Initiation

2021 ◽  
Author(s):  
Chaowei Jiang ◽  
Xueshang Feng ◽  
Rui Liu ◽  
Xiaoli Yan ◽  
Qiang Hu ◽  
...  
Keyword(s):  
Source Region ◽  
Three Dimensional ◽  
Flux Rope ◽  
Null Point ◽  
Magnetic Flux Rope ◽  
Solar Eruptions ◽  
Magnetohydrodynamic Simulations ◽  
Magnetic Null ◽  
Shearing Motion ◽  
Magnetic Null Point

<p>Solar eruptions are spectacular magnetic explosions in the Sun's corona and how they are initiated remains unclear. Prevailing theories often rely on special magnetic topologies, such as magnetic flux rope and magnetic null point, which, however, may not generally exist in the pre-eruption source region of corona. Here using fully three-dimensional magnetohydrodynamic simulations with high accuracy, we show that solar eruption can be initiated in a single bipolar configuration with no additional special topology. Through photospheric shearing motion alone, an electric current sheet forms in the highly sheared core field of the magnetic arcade during its quasi-static evolution. Once magnetic reconnection sets in, the whole arcade is expelled impulsively, forming a fast-expanding twisted flux rope with a highly turbulent reconnecting region underneath. The simplicity and efficacy of this scenario argue strongly for its fundamental importance in the initiation of solar eruptions.</p>

scholarly journals Numerical simulations of the CME on 2010 April 8

2012 ◽  
Vol 8 (S294) ◽  
pp. 575-576
Author(s):  
Yingna Su ◽  
Bernhard Kliem ◽  
Adriaan van Ballegooijen ◽  
Edward Deluca
Keyword(s):  
Magnetic Field ◽  
Stable Equilibrium ◽  
Free Field ◽  
Flux Rope ◽  
Stable Model ◽  
Mhd Simulations ◽  
Insertion Method ◽  
Ideal Mhd ◽  
Nonlinear Force ◽  
Force Free Field

AbstractWe present 3D zero-beta ideal MHD simulations of the solar flare/CME event that occurred in Active Region 11060 on 2010 April 8. The initial magnetic configurations of the two simulations are stable nonlinear force-free field and unstable magnetic field models constructed by Su et al. (2011) using the flux rope insertion method. The MHD simulations confirm that the stable model relaxes to a stable equilibrium, while the unstable model erupts as a CME. Comparisons between observations and MHD simulations of the CME are also presented.

Storm time ring current magnetic field modeling during May 15, 1997 event

2002 ◽  
Vol 30 (10) ◽  
pp. 2175-2180 ◽  
Author(s):  
N.Yu. Ganushkina ◽  
T.I. Pulkkinen ◽  
M.V. Kubyshkina
Keyword(s):  
Magnetic Field ◽  
Ring Current ◽  
Field Modeling ◽  
Magnetic Field Modeling ◽  
Current Magnetic Field

scholarly journals Processes and mechanisms governing the initiation and propagation of CMEs

2008 ◽  
Vol 26 (10) ◽  
pp. 3089-3101 ◽  
Author(s):  
B. Vršnak
Keyword(s):  
Magnetic Flux ◽  
External Disturbance ◽  
Source Region ◽  
Flux Rope ◽  
Impulsive Phase ◽  
3 Dimensional ◽  
Initiation And Propagation ◽  
Region Size ◽  
The Magnetic Field

Abstract. The most important observational characteristics of coronal mass ejections (CMEs) are summarized, emphasizing those aspects which are relevant for testing physical concepts employed to explain the CME take-off and propagation. In particular, the kinematics, scalings, and the CME-flare relationship are stressed. Special attention is paid to 3-dimensional (3-D) topology of the magnetic field structures, particularly to aspects related to the concept of semi-toroidal flux-rope anchored at both ends in the dense photosphere and embedded in the coronal magnetic arcade. Observations are compared with physical principles and concepts employed in explaining the CME phenomenon, and implications are discussed. A simple flux-rope model is used to explain various stages of the eruption. The model is able to reproduce all basic observational requirements: stable equilibrium and possible oscillations around equilibrium, metastable state and possible destabilization by an external disturbance, pre-eruptive gradual-rise until loss of equilibrium, possibility of fallback events and failed eruptions, relationship between impulsiveness of the CME acceleration and the source-region size, etc. However, it is shown that the purely ideal MHD process cannot account for highest observed accelerations which can attain values up to 10 km s−2. Such accelerations can be achieved if the process of reconnection beneath the erupting flux-rope is included into the model. Essentially, the role of reconnection is in changing the magnetic flux associated with the flux-rope current and supplying "fresh" poloidal magnetic flux to the rope. These effects help sustain the electric current flowing along the flux-rope, and consequently, reinforce and prolong the CME acceleration. The model straightforwardly explains the observed synchronization of the flare impulsive phase and the CME main-acceleration stage, as well as the correlations between various CME and flare parameters.

Sign in / Sign up

Export Citation Format

Share Document