scholarly journals Equilibrium of the Return-Current Sheet and Structure of the Pulsar Magnetosphere

1992 ◽  
Vol 128 ◽  
pp. 112-113
Author(s):  
Yu. E. Lyubarskii
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Neutron Stars ◽  
Current Sheet ◽  
Equilibrium Condition ◽  
Pulsar Magnetosphere ◽  
Field Lines ◽  
Current Flows ◽  
Magnetic Poles ◽  
Open Magnetic Field

Pulsars are generally identified with rotating, magnetized neutron stars. According to Goldreich and Julian (1969), an induced electric field creates the electric current which flows out of the magnetic poles and fills the magnetosphere with plasma. The current flows along the open magnetic field lines and returns along the boundary between the closed and open parts of the magnetosphere (Scharlemann and Wagoner 1973). The boundary shape is determined by the equilibrium condition for the current sheet.

Quasi Periodic Oscillations in the Pre Phases of Recurrent Jets Highlighting Plasmoids in Current Sheet

2020 ◽  
Author(s):  
Reetika Joshi ◽  
Ramesh Chandra ◽  
Brigitte Schmieder ◽  
Guillaume Aulanier ◽  
Pooja Devi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Current Sheet ◽  
The Other ◽  
Active Region Noaa ◽  
The West ◽  
Periodic Oscillations ◽  
West Limb ◽  
Field Lines ◽  
Open Magnetic Field ◽  
Double Chamber

<p><strong>Solar jets observed at the limb are important to determine the location of reconnection sites in the corona. In this study, we investigate six recurrent hot and cool jets occurring in the active region NOAA 12644 as it is crossing the west limb on April 04, 2017. These jets are observed in all the UV/EUV filters of SDO/AIA and in cooler temperature formation lines in IRIS slit jaw images. The jets are initiated at the top of a double chamber vault with cool loops on one side and hot loops on the other side. The existence of such double chamber vaults suggests the presence of emerging flux with cool loops, the hot loops being the reconnected loops similarly as in the models of Moreno-</strong><strong>Insertis</strong><strong>et al. 2008, 2013 and Nóbrega-Siverio et al. 2016. In the preliminary phase of the main jets, </strong><strong>quasi periodic</strong><strong> intensity oscillations accompanied by smaller jets are detected in the bright current sheet between the vault and the preexisting magnetic field. Individual kernels and plasmoids are ejected in open field lines </strong><strong>along</strong><strong> the jets. Plasmoids may launch torsional Alfven waves and the kernels would be the result of the </strong><strong>untwist</strong><strong> of the plasmoids in open magnetic field as proposed in the model of Wyper et al. 2016.</strong></p>

scholarly journals Mapping of steady-state electric fields and convective drifts in geomagnetic fields – Part 1: Elementary models

2016 ◽  
Vol 34 (1) ◽  
pp. 55-65 ◽  
Author(s):  
A. D. M. Walker ◽  
G. J. Sofko
Keyword(s):  
Magnetic Field ◽  
Steady State ◽  
Electric Field ◽  
Electric Fields ◽  
Magnetic Field Line ◽  
Geomagnetic Field ◽  
Geomagnetic Field Models ◽  
Spatial Derivatives ◽  
Field Lines ◽  
The Magnetic Field

Abstract. When studying magnetospheric convection, it is often necessary to map the steady-state electric field, measured at some point on a magnetic field line, to a magnetically conjugate point in the other hemisphere, or the equatorial plane, or at the position of a satellite. Such mapping is relatively easy in a dipole field although the appropriate formulae are not easily accessible. They are derived and reviewed here with some examples. It is not possible to derive such formulae in more realistic geomagnetic field models. A new method is described in this paper for accurate mapping of electric fields along field lines, which can be used for any field model in which the magnetic field and its spatial derivatives can be computed. From the spatial derivatives of the magnetic field three first order differential equations are derived for the components of the normalized element of separation of two closely spaced field lines. These can be integrated along with the magnetic field tracing equations and Faraday's law used to obtain the electric field as a function of distance measured along the magnetic field line. The method is tested in a simple model consisting of a dipole field plus a magnetotail model. The method is shown to be accurate, convenient, and suitable for use with more realistic geomagnetic field models.

scholarly journals A Look into Students' Interpretation of Electric Field Lines

2017 ◽  
pp. 342-364
Author(s):  
Esmeralda Campos ◽  
Genaro Zavala
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Random Sample ◽  
Qualitative Approach ◽  
Undergraduate Level ◽  
Field Lines

On Electricity & Magnetism (EM) courses at undergraduate level, the concept of electric field poses one of the most relevant and basic topics, along with the concept of magnetic field. Professors and students may use different diagrams as a tool to visualize the electric field, such as vectors or electric field lines. The present study aims to identify how students interpret and use electric field lines as a tool or resource to describe the electric field. Two versions of a test with open-ended questions were administered in Spanish in a private Mexican university to a random sample of students taking the EM course, and were analyzed with a qualitative approach. It was found that students do not interpret electric field lines diagrams correctly, which may lead to misconceptions. Many students based their answers on the concepts of superposition, force and repulsion.

scholarly journals Electron Outflow in Axisymmetric Pulsar Magnetospheres

1985 ◽  
Vol 38 (5) ◽  
pp. 749 ◽  
Author(s):  
RR Burman
Keyword(s):  
Magnetic Field ◽  
Pulsar Magnetosphere ◽  
Poloidal Magnetic Field ◽  
Light Cylinder ◽  
Field Lines ◽  
Limiting Surface

Mestel et al. (1985) have recently introduced an axisymmetric pulsar magnetosphere model in which electrons leave the star with speeds that are non-negligible, but not highly relativistic, and flow with moderate acceleration, and with poloidal motion that is closely tied to the poloidal magnetic field lines, before reaching a limiting surface, near which rapid acceleration occurs. This paper presents an analysis of flows which either encounter the limiting surface beyond the light cylinder or do not meet it at all.

Collisionless plasma transport mechanisms in stochastic open magnetic field lines in tokamaks

2021 ◽  
Author(s):  
Min-Gu Yoo ◽  
Weixing Wang ◽  
Edward A Startsev ◽  
Chenhao Ma ◽  
S Ethier ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Collisionless Plasma ◽  
Plasma Transport ◽  
Transport Mechanisms ◽  
Field Lines ◽  
Open Magnetic Field

scholarly journals Dynamical Galactic Halos

1993 ◽  
Vol 157 ◽  
pp. 415-419
Author(s):  
D. Breitschwerdt ◽  
H.J. Völk ◽  
V. Ptuskin ◽  
V. Zirakashvili
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
The Other ◽  
Galactic Rotation ◽  
Galactic Halos ◽  
Magnetic Forces ◽  
Dynamical Coupling ◽  
Field Lines ◽  
The Magnetic Field ◽  
Open Magnetic Field

It is argued that the description of the magnetic field in halos of galaxies should take into account its dynamical coupling to the other major components of the interstellar medium, namely thermal plasma and cosmic rays (CR's). It is then inevitable to have some loss of gas and CR's (galactic wind) provided that there exist some “open” magnetic field lines, facilitating their escape, and a sufficient level of self-generated waves which couple the particles to the gas. We discuss qualitatively the topology of the magnetic field in the halo and show how galactic rotation and magnetic forces can be included in such an outflow picture.

scholarly journals Very High-Energy Emission from the Direct Vicinity of Rapidly Rotating Black Holes

Galaxies ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 122 ◽  
Author(s):  
Kouichi Hirotani
Keyword(s):  
Magnetic Field ◽  
Black Holes ◽  
Black Hole ◽  
Electric Field ◽  
Gamma Rays ◽  
Accretion Rate ◽  
High Energy ◽  
Relativistic Electrons ◽  
Field Lines ◽  
The Magnetic Field

When a black hole accretes plasmas at very low accretion rate, an advection-dominated accretion flow (ADAF) is formed. In an ADAF, relativistic electrons emit soft gamma-rays via Bremsstrahlung. Some MeV photons collide with each other to materialize as electron-positron pairs in the magnetosphere. Such pairs efficiently screen the electric field along the magnetic field lines, when the accretion rate is typically greater than 0.03–0.3% of the Eddington rate. However, when the accretion rate becomes smaller than this value, the number density of the created pairs becomes less than the rotationally induced Goldreich–Julian density. In such a charge-starved magnetosphere, an electric field arises along the magnetic field lines to accelerate charged leptons into ultra-relativistic energies, leading to an efficient TeV emission via an inverse-Compton (IC) process, spending a portion of the extracted hole’s rotational energy. In this review, we summarize the stationary lepton accelerator models in black hole magnetospheres. We apply the model to super-massive black holes and demonstrate that nearby low-luminosity active galactic nuclei are capable of emitting detectable gamma-rays between 0.1 and 30 TeV with the Cherenkov Telescope Array.

Ballooning modes on open magnetic field lines

1999 ◽  
Vol 6 (3) ◽  
pp. 674-685 ◽  
Author(s):  
Eliezer Hameiri
Keyword(s):  
Magnetic Field ◽  
Field Lines ◽  
Open Magnetic Field
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