A Numerical Study of Magnetic Reconnection Driven by an Emerging Of Magnetic Flux

2000 ◽  
Vol 43 (1) ◽  
pp. 1-11
Author(s):  
Shou-Jun SU ◽  
Shui WANG
Keyword(s):  
Magnetic Flux ◽  
Magnetic Reconnection ◽  
Numerical Study

scholarly journals Numerical study of the reconnection process between magnetic cloud and heliospheric current sheet

2018 ◽  
Vol 619 ◽  
pp. A82
Author(s):  
Man Zhang ◽  
Yu Fen Zhou ◽  
Xue Shang Feng ◽  
Bo Li ◽  
Ming Xiong
Keyword(s):  
Magnetic Reconnection ◽  
Current Sheet ◽  
Dynamic Process ◽  
Large Scale ◽  
Magnetic Cloud ◽  
Numerical Study ◽  
Three Dimensional ◽  
Heliospheric Current Sheet ◽  
Reconnection Process ◽  
Magnetic Filed

In this paper, we have used a three-dimensional numerical magnetohydrodynamics model to study the reconnection process between magnetic cloud and heliospheric current sheet. Within a steady-state heliospheric model that gives a reasonable large-scale structure of the solar wind near solar minimum, we injected a spherical plasmoid to mimic a magnetic cloud. When the magnetic cloud moves to the heliospheric current sheet, the dynamic process causes the current sheet to become gradually thinner and the magnetic reconnection begin. The numerical simulation can reproduce the basic characteristics of the magnetic reconnection, such as the correlated/anticorrelated signatures in V and B passing a reconnection exhaust. Depending on the initial magnetic helicity of the cloud, magnetic reconnection occurs at points along the boundary of the two systems where antiparallel field lines are forced together. We find the magnetic filed and velocity in the MC have a effect on the reconnection rate, and the magnitude of velocity can also effect the beginning time of reconnection. These results are helpful in understanding and identifying the dynamic process occurring between the magnetic cloud and the heliospheric current sheet.

Interaction of Magnetic Flux Ropes Via Magnetic Reconnection Observed at the Magnetopause

2017 ◽  
Vol 122 (10) ◽  
pp. 10,436-10,447 ◽  
Author(s):  
Rongsheng Wang ◽  
Quanming Lu ◽  
Rumi Nakamura ◽  
Wolfgang Baumjohann ◽  
C. T. Russell ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Magnetic Reconnection ◽  
Magnetic Flux Ropes ◽  
Flux Ropes

Magnetic flux array for spontaneous magnetic reconnection experiments

2008 ◽  
Vol 79 (6) ◽  
pp. 063505 ◽  
Author(s):  
A. Kesich ◽  
J. Bonde ◽  
J. Egedal ◽  
W. Fox ◽  
R. Goodwin ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Magnetic Reconnection

Effect of plasma-β on the onset of plasmoid instability in Sweet–Parker current sheets

2014 ◽  
Vol 80 (5) ◽  
pp. 655-665 ◽  
Author(s):  
H. Baty
Keyword(s):  
Magnetic Reconnection ◽  
Temperature Increase ◽  
Numerical Study ◽  
Two Dimensional ◽  
Magnetic Island ◽  
Current Sheets ◽  
A Value ◽  
Similar Dependence ◽  
Definition Of ◽  
Local Temperature Increase

AbstractA numerical study of magnetic reconnection in two-dimensional resistive magnetohydrodynamics for Sweet–Parker current sheets that are subject to plasmoid instability is carried out. The effect of the initial upstream plasma-β on the critical Lundquist number Sc for the onset of plasmoid instability is studied. Our results indicate a weak dependence, with a value of Sc ≃ 1.5 × 104 in the limit of zero β, and a value of Sc ≃ 1 × 104 in the opposite high β regime (β ≫ 1). A similar dependence was previously obtained (Ni et al. 2012 Phys. Plasm. 19, 072902), but with a somewhat much larger variation, that can be largely attributed to the different configuration setup used in their study, and also to the definition of the Lundquist number. This conclusion does not depend significantly on the equilibrium used, i.e. both initial configurations with either plasma density or temperature spatial variations lead to very similar results. Finally, we show that the inner plasmoid structure appears as an under-dense hotted magnetic island, with a local temperature increase that is noticeably strengthened for low β cases.

scholarly journals Turbulence and dynamo interlinks

2012 ◽  
Vol 8 (S294) ◽  
pp. 337-348
Author(s):  
E. M. de Gouveia Dal Pino ◽  
R. Santos-Lima ◽  
G. Kowal ◽  
D. Falceta-Gonçalves
Keyword(s):  
Magnetic Fields ◽  
Magnetic Flux ◽  
Magnetic Reconnection ◽  
Small Scale ◽  
Low Density ◽  
Mhd Turbulence ◽  
Turbulent Dynamo ◽  
Dynamo Process

AbstractThe role of turbulence in astrophysical environments and its interplay with magnetic fields is still highly debated. In this lecture, we will discuss this issue in the framework of dynamo processes. We will first present a very brief summary of turbulent dynamo theories, then will focus on small scale turbulent dynamos and their particular relevance on the origin and maintenance of magnetic fields in the intra-cluster media (ICM) of galaxies. In these environments, the very low density of the flow requires a collisionless-MHD treatment. We will show the implications of this approach in the turbulent amplification of the magnetic fields in these environments. To finalize, we will also briefly address the connection between MHD turbulence and fast magnetic reconnection and its possible implications in the diffusion of magnetic flux in the dynamo process.

scholarly journals A new trigger mechanism for coronal mass ejections

2020 ◽  
Vol 644 ◽  
pp. A137
Author(s):  
A. W. James ◽  
L. M. Green ◽  
L. van Driel-Gesztelyi ◽  
G. Valori
Keyword(s):  
Magnetic Flux ◽  
Magnetic Reconnection ◽  
Extreme Ultraviolet ◽  
Flux Rope ◽  
Active Regions ◽  
Magnetic Activity ◽  
Trigger Mechanism ◽  
Magnetic Flux Rope ◽  
Left Handed ◽  
Flux Ropes

Context. Many previous studies have shown that the magnetic precursor of a coronal mass ejection (CME) takes the form of a magnetic flux rope, and a subset of them have become known as “hot flux ropes” due to their emission signatures in ∼10 MK plasma. Aims. We seek to identify the processes by which these hot flux ropes form, with a view of developing our understanding of CMEs and thereby improving space weather forecasts. Methods. Extreme-ultraviolet observations were used to identify five pre-eruptive hot flux ropes in the solar corona and study how they evolved. Confined flares were observed in the hours and days before each flux rope erupted, and these were used as indicators of episodic bursts of magnetic reconnection by which each flux rope formed. The evolution of the photospheric magnetic field was observed during each formation period to identify the process(es) that enabled magnetic reconnection to occur in the β <  1 corona and form the flux ropes. Results. The confined flares were found to be homologous events and suggest flux rope formation times that range from 18 hours to 5 days. Throughout these periods, fragments of photospheric magnetic flux were observed to orbit around each other in sunspots where the flux ropes had a footpoint. Active regions with right-handed (left-handed) twisted magnetic flux exhibited clockwise (anticlockwise) orbiting motions, and right-handed (left-handed) flux ropes formed. Conclusions. We infer that the orbital motions of photospheric magnetic flux fragments about each other bring magnetic flux tubes together in the corona, enabling component reconnection that forms a magnetic flux rope above a flaring arcade. This represents a novel trigger mechanism for solar eruptions and should be considered when predicting solar magnetic activity.

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