scholarly journals Publisher's Note: “Effects of a velocity shear on double current sheet systems: Explosive reconnection and particle acceleration” [Phys. Plasmas 28, 082903 (2021)]

2022 ◽  
Vol 29 (1) ◽  
pp. 019901
Author(s):  
Arghyadeep Paul ◽  
Bhargav Vaidya
Keyword(s):  
Particle Acceleration ◽  
Current Sheet ◽  
Velocity Shear

scholarly journals Hybrid numerical simulations of pulsar magnetospheres

2019 ◽  
Vol 491 (4) ◽  
pp. 5579-5585 ◽  
Author(s):  
Ioannis Contopoulos ◽  
Jerome Pétri ◽  
Petros Stefanou
Keyword(s):  
Particle Acceleration ◽  
Current Sheet ◽  
Electric Current ◽  
Hybrid Approach ◽  
High Energy ◽  
Basic Premise ◽  
Analytic Approximations ◽  
Polar Caps ◽  
Electron Positron ◽  
Field Lines

ABSTRACT We continue our investigation of particle acceleration in the pulsar equatorial current sheet (ECS). Our basic premise has been that the charge carriers in the current sheet originate in the polar caps as electron–positron pairs, and are carried along field lines that enter the ECS beyond the magnetospheric Y-point. In this work, we investigate further the charge replenishment of the ECS. We discovered that the flow of pairs from the rims of the polar caps cannot supply both the electric charge and the electric current of the ECS. The ECS must contain an extra amount of positronic (or electronic depending on orientation) electric current that originates in the stellar surface and flows outwards along the separatrices. We develop an iterative hybrid approach that self-consistently combines ideal force-free electrodynamics in the bulk of the magnetosphere with particle acceleration along the ECS. We derive analytic approximations for the orbits of the particles, and obtain the structure of the pulsar magnetosphere for various values of the pair formation multiplicity parameter κ. For realistic values κ ≫ 1, the magnetosphere is practically indistinguishable from the ideal force-free one, and therefore, the calculation of the spectrum of high energy radiation must rely on analytic approximations for the distribution of the accelerating electric field in the ECS.

PARTICLE ACCELERATION AND MAGNETIC FIELD GENERATION IN SHEAR-FLOWS

2014 ◽  
Vol 28 ◽  
pp. 1460195
Author(s):  
K.-I. NISHIKAWA ◽  
P. HARDEE ◽  
Y. MIZUNO ◽  
I. DUŢAN ◽  
B. ZHANG ◽  
...  
Keyword(s):  
Particle Acceleration ◽  
Magnetic Fields ◽  
Lorentz Factor ◽  
Velocity Shear ◽  
Magnetic Field Generation ◽  
Electron Positron ◽  
Relativistic Jet ◽  
Unmagnetized Plasma ◽  
Alternating Magnetic Fields ◽  
Transverse Deflection

We have investigated the generation of magnetic fields associated with velocity shear between an unmagnetized relativistic (core) jet and an unmagnetized sheath plasma by the kinetic Kelvin-Helmholtz instability for different mass ratios (m i /m e = 1, 20, and 1836) and different jet Lorentz factors. We found that electron-positron cases have alternating magnetic fields instead of the DC magnetic fields found in electron-ion cases. We have also investigated particle acceleration and shock structure associated with an unmagnetized relativistic jet propagating into an unmagnetized plasma for electron-positron and electron-ion plasmas. Strong magnetic fields generated in the trailing shock lead to transverse deflection and acceleration of the electrons. We have self-consistently calculated the radiation from the electrons accelerated in the turbulent magnetic fields for different jet Lorentz factors. We find that the synthetic spectra depend on the bulk Lorentz factor of the jet, the jet temperature, and the strength of the magnetic fields generated in the shock.

Particle Acceleration Asymmetry in a Reconnecting Nonneutral Current Sheet

2004 ◽  
Vol 604 (2) ◽  
pp. 884-891 ◽  
Author(s):  
Valentina V. Zharkova ◽  
Mykola Gordovskyy
Keyword(s):  
Particle Acceleration ◽  
Current Sheet

scholarly journals Bifurcated Current Sheet Observed on the Boundary of Kelvin-Helmholtz Vortices

2021 ◽  
Vol 8 ◽  
Author(s):  
K-J. Hwang ◽  
K. Dokgo ◽  
E. Choi ◽  
J. L. Burch ◽  
D. G. Sibeck ◽  
...  
Keyword(s):  
Current Sheet ◽  
Layer Structure ◽  
Velocity Shear ◽  
Current Layer ◽  
Combined Effects ◽  
Slow Mode ◽  
Flow Shear ◽  
Current Sheets ◽  
Guide Field ◽  
Line Region

On May 5, 2017 MMS observed a bifurcated current sheet at the boundary of Kelvin-Helmholtz vortices (KHVs) developed on the dawnside tailward magnetopause. We use the event to enhance our understanding of the formation and structure of asymmetric current sheets in the presence of density asymmetry, flow shear, and guide field, which have been rarely studied. The entire current layer comprises three separate current sheets, each corresponding to magnetosphere-side sunward separatrix region, central near-X-line region, and magnetosheath-side tailward separatrix region. Two off-center structures are identified as slow-mode discontinuities. All three current sheets have a thickness of ∼0.2 ion inertial length, demonstrating the sub-ion-scale current layer, where electrons mainly carry the current. We find that both the diamagnetic and electron anisotropy currents substantially support the bifurcated currents in the presence of density asymmetry and weak velocity shear. The combined effects of strong guide field, low density asymmetry, and weak flow shear appear to lead to asymmetries in the streamlines and the current-layer structure of the quadrupolar reconnection geometry. We also investigate intense electrostatics waves observed on the magnetosheath side of the KHV boundary. These waves may pre-heat a magnetosheath population that is to participate into the reconnection process, leading to two-step energization of the magnetosheath plasma entering into the magnetosphere via KHV-driven reconnection.

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