scholarly journals Magnetic Energy Release in Relativistic Plasma

2011 ◽  
Vol 7 (S279) ◽  
pp. 405-406
Author(s):  
Hiroyuki R. Takahashi ◽  
Ken Ohsuga
Keyword(s):  
Energy Conversion ◽  
Magnetic Reconnection ◽  
Current Sheet ◽  
Conversion Rate ◽  
Radiation Effects ◽  
Magnetic Energy ◽  
Realistic Model ◽  
Tearing Instability ◽  
First Results ◽  
Time Variations

AbstractThe efficiency of the energy conversion rate in the relativistic magnetic reconnection is investigated by means of Relativistic Resistive Magnetohydrodynamic (R2MHD) simulations. We confirmed that the simple Sweet-Parker type magnetic reconnection is a slow process for the energy conversion as theoretically predicted by Lyubarsky (2005). After the Sweet-Parker regime, we found a growth of the secondary tearing instability in the elongated current sheet. Then the energy conversion rate and the outflow velocity of reconnection jet increase rapidly. Such a rapid energy conversion would explain the time variations observed in many astrophysical flaring events.To construct a more realistic model of relativistic reconnection, we extend our R2MHD code to R3MHD code by including the radiation effects (Relativistic Resistive Radiation Magnetohydrodynamics R3MHD). The radiation field is described by the 0th and 1st moments of the radiation intensity (Farris et al. 2008, Shibata et al. 2011). The code has already passed some one-dimensional and multi-dimensional numerical problems. We demonstrate the first results of magnetic reconnection in the radiation dominated current sheet.

scholarly journals Magnetic-field annihilation and island formation in electron-scale current sheet in Earth's magnetotail

2020 ◽  
Author(s):  
Hiroshi Hasegawa ◽  
Richard Denton ◽  
Kevin Genestreti ◽  
Takuma Nakamura ◽  
Tai Phan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Energy Conversion ◽  
Current Sheet ◽  
Magnetic Energy ◽  
Particle Energy ◽  
Planar Geometry ◽  
Diffusion Region ◽  
Magnetospheric Substorms ◽  
Flow Energy ◽  
The Impact

Abstract Establishing the mechanism of magnetic-to-particle energy conversion through magnetic reconnection in current sheets1 is the key to understanding the impact of fast release of magnetic energy in many space and astrophysical plasma systems, such as during magnetospheric substorms2,3. It is generally believed that an electron-scale diffusion region (EDR), where a magnetic-to-electron energy conversion occurs, has an X-type magnetic-field geometry4 around which the energy of anti-parallel magnetic fields injected is mostly converted to the bulk-flow energy of electrons by magnetic tension of reconnected field-lines5,6. However, it is at present unknown exactly how this energy conversion occurs in EDRs, because there has been no observational method to fully address this problem. Here we present state-of-the-art analysis of multi-spacecraft observations in Earth’s magnetotail of an electron-scale current sheet, which demonstrates that contrary to the standard model of reconnection with an X-type EDR geometry, the fast energy conversion in the detected EDR was caused mostly by magnetic-field annihilation, rather than reconnection. Furthermore, we detected a magnetic island forming in the EDR itself, implying that the EDR had an elongated shape ideal for island generation7 and magnetic-field annihilation. The experimental discovery of the annihilation-dominated EDR reveals a new form of energy conversion in the reconnection process that can occur when the EDR has evolved from the X-type to planar geometry.

Filamentary Currents in Turbulent Magnetic Reconnection

2020 ◽  
Author(s):  
Meng Zhou ◽  
Xiaohua Deng ◽  
Zhihong Zhong ◽  
Ye Pang
Keyword(s):  
Plasma Physics ◽  
Magnetic Reconnection ◽  
Current Sheet ◽  
Coherent Structures ◽  
High Speed ◽  
Large Scale ◽  
Magnetic Energy ◽  
Normal Direction ◽  
Neutral Sheet ◽  
Current Filaments

<p>Magnetic reconnection and turbulence are the two most important energy conversion phenomena in plasma physics. Magnetic reconnection and turbulence are often intertwined. For example, reconnection occurs in thin current layers formed during cascades of turbulence, while reconnection in large-scale current sheet also evolves into turbulence. How energy is dissipated and how particles are accelerated in turbulent magnetic reconnection are outstanding questions in magnetic reconnection and turbulence. Here we report MMS observations of filamentary currents in turbulent outflows in the Earth's magnetotail. We found sub-ion-scale filamentary currents in high-speed outflows that evolved into turbulent states. The normal direction of these current filaments is mainly along the X<sub>GSM</sub> direction, which is distinct from the neutral sheet. Some filamentary currents were reconnecting, thereby further dissipating the magnetic energy far from the X line. We notice that turbulent reconnection is more efficient in energizing electrons than laminar reconnection. Coherent structures composed of these filaments may be important in accelerating particles during turbulent reconnection.  </p>

scholarly journals Three-dimensional simulations of magnetic reconnection in a dusty plasma

2008 ◽  
Vol 74 (4) ◽  
pp. 493-513 ◽  
Author(s):  
SAMUEL A. LAZERSON ◽  
HEINZ M. WIECHEN
Keyword(s):  
Magnetic Reconnection ◽  
Current Sheet ◽  
Dusty Plasma ◽  
Aerodynamic Drag ◽  
Magnetic Energy ◽  
Three Dimensional ◽  
Dust Particles ◽  
Classical Models ◽  
Parameter Dependent ◽  
Three Dimensional Simulations

AbstractWe present the results of three-dimensional self-consistent multi-fluid simulations of magnetic reconnection in a dusty plasma. We ballistically relax a Harris-like current sheet into a fluid pseudo-equilibrium. We then perturb the current sheet with typical inflow and outflow velocities associated with classical models of reconnection. We find a 20% decrease in magnetic energy for the case of a locally enhanced resistivity. For a parameter-dependent resistivity we find a 26% decrease in magnetic energy in the current sheet. We find dust-neutral relative flow velocities that are a factor of two greater than the dust Alfvén velocity. We then explore the implications of these flows on aerodynamic drag heating of the dust particles.

scholarly journals EVOLUTION OF PLASMOID-CHAIN IN POYNTING-DOMINATED PLASMA

2014 ◽  
Vol 28 ◽  
pp. 1460170
Author(s):  
MAKOTO TAKAMOTO
Keyword(s):  
Magnetic Reconnection ◽  
Current Sheet ◽  
Physical Mechanism ◽  
Temporal Evolution ◽  
High Energy ◽  
Critical Value ◽  
Numerical Results ◽  
Background Plasma ◽  
Reconnection Rate ◽  
Tearing Instability

We present our recent results of the evolution of the plasmoid-chain in a Poynting dominated plasma. We model the relativistic current sheet with cold background plasma using the relativistic resistive magnetohydrodynamic approximation, and solve its temporal evolution numerically. Numerical results show that the initially induced plasmoid triggers a secondary tearing instability. We find the plasmoid-chain greatly enhances the reconnection rate, which becomes independent of the Lundquist number, when this exceeds a critical value. Since magnetic reconnection is expected to play an important role in various high energy astrophysical phenomena, our results can be used for explaining the physical mechanism of them.

Direct evidence of secondary reconnection inside filamentary currents of magnetic flux ropes in magnetic reconnection

2020 ◽  
Author(s):  
Shimou Wang ◽  
Quanming Lu
Keyword(s):  
Energy Dissipation ◽  
Magnetic Flux ◽  
Magnetic Reconnection ◽  
Current Sheet ◽  
Magnetic Energy ◽  
Flux Rope ◽  
Plasma Jets ◽  
Magnetic Flux Ropes ◽  
Flux Ropes ◽  
Reconnecting Current Sheet

<p>Magnetic reconnection is a fundamental plasma process, by which magnetic energy is explosively released in the current sheet to energize charged particles and to create bi-directional Alfvénic plasma jets. A long-outstanding issue is how the stored magnetic energy is rapidly released in the process. Numerical simulations and observations show that formation and interaction of magnetic flux ropes dominate the evolution of the reconnecting current sheet. Accordingly, most volume of the reconnecting current sheet is occupied by the flux ropes and energy dissipation primarily occurs along their edges via the flux rope coalescence. Here, for the first time, we present in-situ evidence of magnetic reconnection inside the filamentary currents which was driven possibly by electron vortices inside the flux ropes. Our results reveal an important new way for energy dissipation in magnetic reconnection.</p>

scholarly journals Observational Signatures of Tearing Instability in the Current Sheet of a Solar Flare

2022 ◽  
Vol 924 (1) ◽  
pp. L7
Author(s):  
Lei Lu ◽  
Li Feng ◽  
Alexander Warmuth ◽  
Astrid M. Veronig ◽  
Jing Huang ◽  
...  
Keyword(s):  
Solar Flare ◽  
Magnetic Reconnection ◽  
Current Sheet ◽  
Extreme Ultraviolet ◽  
Magnetic Energy ◽  
Plasma Heating ◽  
Particle Energy ◽  
Transport Processes ◽  
Data Set ◽  
Plasma Energy

Abstract Magnetic reconnection is a fundamental physical process converting magnetic energy into not only plasma energy but also particle energy in various astrophysical phenomena. In this Letter, we show a unique data set of a solar flare where various plasmoids were formed by a continually stretched current sheet. Extreme ultraviolet images captured reconnection inflows, outflows, and particularly the recurring plasma blobs (plasmoids). X-ray images reveal nonthermal emission sources at the lower end of the current sheet, presumably as large plasmoids with a sufficiently amount of energetic electrons trapped in them. In the radio domain, an upward, slowly drifting pulsation structure, followed by a rare pair of oppositely drifting structures, was observed. These structures are supposed to map the evolution of the primary and the secondary plasmoids formed in the current sheet. Our results on plasmoids at different locations and scales shed important light on the dynamics, plasma heating, particle acceleration, and transport processes in the turbulent current sheet and provide observational evidence for the cascading magnetic reconnection process.

scholarly journals On the Energy Conversion Rate during Collisionless Magnetic Reconnection

2019 ◽  
Vol 883 (1) ◽  
pp. L22 ◽  
Author(s):  
Yongyuan Yi ◽  
Meng Zhou ◽  
Liangjin Song ◽  
Xiaohua Deng
Keyword(s):  
Energy Conversion ◽  
Magnetic Reconnection ◽  
Conversion Rate

Tearing instability inside a 2D current sheet with a normal magnetic field

2021 ◽  
Author(s):  
Chen Shi ◽  
Anton Artemyev ◽  
Marco Velli ◽  
Anna Tenerani
Keyword(s):  
Magnetic Field ◽  
Magnetic Reconnection ◽  
Current Sheet ◽  
Normal Component ◽  
Field Energy ◽  
Tearing Mode ◽  
Magnetic Field Energy ◽  
Tearing Instability ◽  
The Magnetic Field ◽  
Normal Magnetic Field

<p>Magnetic reconnection converts the magnetic field energy into thermal and kinetic energies of the plasma. This process usually happens at extremely fast speed and is therefore believed to be a fundamental mechanism to explain various explosive phenomena such as coronal mass ejections and planetary magnetospheric storms. How magnetic reconnection is triggered from the large magnetohydrodynamic (MHD) scales remains an open question, with some theoretical and numerical studies showing the tearing instability to be involved. Observations in the Earth’s magnetotail and near the magnetopause show that a finite normal magnetic field is usually present inside the reconnecting current sheet. Besides, such a normal field may also exist in the solar corona. However, how this normal magnetic field modifies the tearing instability is not thoroughly studied. Here we discuss the linear tearing instability inside a two-dimensional current sheet with a normal component of magnetic field where the magnetic tension force is balanced by ion flows parallel and anti-parallel to the magnetic field. We solve the dispersion relation of the tearing mode with wave vector parallel to the reconnecting magnetic field. Our results confirm that the finite normal magnetic field stabilizes the tearing mode and makes the mode oscillatory instead of purely growing.</p>

Conversion of magnetic energy and the width of current sheets

2002 ◽  
Vol 68 (1) ◽  
pp. 53-58
Author(s):  
MANUEL NÚÑEZ
Keyword(s):  
Energy Transfer ◽  
Magnetic Reconnection ◽  
Current Sheet ◽  
Magnetic Energy ◽  
Plasma Conductivity ◽  
Constant Rate ◽  
Classical Models ◽  
Field Lines ◽  
A Current ◽  
Fast Reconnection

Magnetic reconnection is one of the most efficient ways of transforming magnetic into kinetic and thermal energies. We prove a general identity relating the energy transfer in a neighborhood of a current sheet, where reconnection is assumed to occur. With some reasonable hypotheses regarding the geometry of stream and field lines, we prove that for a constant rate of transformation of magnetic energy, the width of the current sheet must grow with the plasma conductivity. Hence an enhanced diffusivity seems necessary for certain classical models of fast reconnection to work.

Sign in / Sign up

Export Citation Format

Share Document