The Evolution of Collisionless Magnetic Reconnection from Electron Scales to Ion Scales

2021 ◽  
Vol 922 (1) ◽  
pp. 51
Author(s):  
Dongkuan Liu ◽  
Kai Huang ◽  
Quanming Lu ◽  
San Lu ◽  
Rongsheng Wang ◽  
...  

Abstract It is generally accepted that collisionless magnetic reconnection is initiated on electron scales, which is mediated by electron kinetics. In this paper, by performing a two-dimensional particle-in-cell simulation, we investigate the transition of collisionless magnetic reconnection from electron scales to ion scales in a Harris current sheet with and without a guide field. The results show that after magnetic reconnection is triggered on electron scales, the electrons are first accelerated by the reconnection electric field around the X line, and then leave away along the outflow direction. In the Harris current sheet without a guide field, the electron outflow is symmetric and directed away from the X line along the center of the current sheet, while the existence of a guide field will distort the symmetry of the electron outflow. In both cases, the high-speed electron outflow is decelerated due to the existence of the magnetic field B z , then leading to the pileup of B z . With the increase of B z , the ions are accelerated by the Lorentz force in the outflow direction, and an ion outflow at about one Alfvén speed is at last formed. In this way, collisionless magnetic reconnection is transferred from the electron scales to the ion scales.

2009 ◽  
Vol 27 (3) ◽  
pp. 471-474 ◽  
Author(s):  
S.Z. Wu ◽  
C.T. Zhou ◽  
X.T. He ◽  
S.-P. Zhu

AbstractA two-layer target irradiated by an intense laser to generate strong interface magnetic field is proposed. The mechanism is analyzed through a simply physical model and investigated by two-dimensional particle-in-cell simulation. The effect of laser intensity on the resulting magnetic field strength is also studied. It is found that the magnetic field can reach up to several ten megagauss for laser intensity at 1019 Wcm−2.


2011 ◽  
Vol 18 (5) ◽  
pp. 727-733 ◽  
Author(s):  
C. Huang ◽  
Q. Lu ◽  
Z. Yang ◽  
M. Wu ◽  
Q. Dong ◽  
...  

Abstract. Two-dimensional (2-D) particle-in-cell (PIC) simulations are performed to investigate the evolution of the electron current sheet (ECS) in guide field reconnection. The ECS is formed by electrons accelerated by the inductive electric field in the vicinity of the X line, which is then extended along the x direction due to the imbalance between the electric field force and Ampere force. The tearing instability is unstable when the ECS becomes sufficiently long and thin, and several seed islands are formed in the ECS. These tiny islands may coalesce and form a larger secondary island in the center of the diffusion region.


2019 ◽  
Vol 46 (16) ◽  
pp. 9352-9361 ◽  
Author(s):  
N. Bessho ◽  
L.‐J. Chen ◽  
S. Wang ◽  
M. Hesse ◽  
L. B. Wilson

2021 ◽  
Vol 919 (1) ◽  
pp. 28
Author(s):  
Quanming Lu ◽  
Zhongwei Yang ◽  
Huanyu Wang ◽  
Rongsheng Wang ◽  
Kai Huang ◽  
...  

2020 ◽  
Author(s):  
Susanne Flø Spinnangr ◽  
Paul Tenfjord ◽  
Michael Hesse ◽  
Cecilia Norgren ◽  
Norah Kwagala

<p>Our group has done extensive research on the fluid and kinetic effect of cold ion populations on the reconnection process, in an effort to identify factors that can lead to the onset or stopping of magnetic reconnection. Recent fully kinetic studies involving cold protons or oxygen have shown that flows of cold particles significantly modify the reconnection process, and that the nature of this modification is dependent on the configuration of these flows and the constituent ions of the flows. In this study we want to investigate how the reconnection process is affected by a shear flow of cold protons outside of the current sheet, using a 2.5D Particle-In-Cell simulation. The effect of shear flows on magnetic reconnection has investigated earlier, indicating a signifficant modification of the reconnection process. However, it is not clear how these effects will be influenced by the additional scale lengths introduced into the system by a cold ion flow. In particular we want to investigate how the current sheet and diffusion regions are altered by a cold shear flow on a kinetic level, and how the reconnection process is altered on ion scales and beyond. Preliminary results indicate that the shear flow introduces a tilt of the current sheet, which appears to be consistent with earlier studies. Results will be compared to our group’s earlier results involving symmetric and asymmetric flows of cold particles in the inflow regions, as well as existing simulations and observations of magnetic reconnection including warm shear flows.</p>


2018 ◽  
Vol 16 (6) ◽  
pp. 385-390
Author(s):  
Shikha BINWAL ◽  
Jay K JOSHI ◽  
Shantanu Kumar KARKARI ◽  
Predhiman Krishan KAW ◽  
Lekha NAIR ◽  
...  

A floating emissive probe has been used to obtain the spatial electron temperature (Te) profile in a 13.56 MHz parallel plate capacitive coupled plasma. The effect of an external transverse magnetic field and pressure on the electron temperature profile has been discussed. In the un-magnetised case, the bulk region of the plasma has a uniform Te. Upon application of the magnetic field, the Te profile becomes non-uniform and skewed.  With increase in pressure, there is an overall reduction in electron temperature. The regions adjacent to the electrodes witnessed a higher temperature than the bulk for both cases. The emissive probe results have also been compared with particle-in-cell simulation results for the un-magnetised case.


2020 ◽  
Author(s):  
Rongsheng Wang

<p>It is still unresolved that how magnetic reconnection is triggered in the collisionless environment. In this talk, we will present that the reconnection onset consists of two phases: the electron phase and ion phase. In the electron phase, the electrons are significantly energized and super-alfvenic electron jets are created while the ion bulk flows haven't been formed and the ions haven't been heated. Later on, the ion jets are produced together with the electron jets in the ion phase. The main reason for such two phases is discussed. A particle-in-cell simulation was performed to realize these two phases during reconnection onset. </p><p> </p>


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