A Wide Field λ90cm Image around the Galactic Centre — Evidence for a Poloidal Magnetic Field

1990 ◽  
pp. 375-376
Author(s):  
K. R. Anantharamaiah ◽  
A. Pedlar
Keyword(s):  
Magnetic Field ◽  
Galactic Centre ◽  
Wide Field ◽  
Poloidal Magnetic Field

scholarly journals A Wide Field λ90cm Image Around the Galactic Centre - Evidence for a Poloidal Magnetic Field

1990 ◽  
Vol 140 ◽  
pp. 375-376
Author(s):  
K. R. Anantharamaiah ◽  
A. Pedlar
Keyword(s):  
Magnetic Field ◽  
Galactic Plane ◽  
Surrounding Medium ◽  
Galactic Centre ◽  
Wide Field ◽  
Pressure Balance ◽  
Poloidal Magnetic Field ◽  
The Galaxy

A number of unique non-thermal filamentary structures, which are all roughly perpendicular to the galactic plane have been discovered in the vicinity of the Galactic centre (see Yusef-Zadeh 1989 and references there in). On the basis of their uniformity, polarization angles, rigidity, and pressure balance with the surrounding medium, it has been hypothesized that a strong polodial field of milligauss strength pervades the inner 50 pc of the Galaxy (Morris and Yusef-Zadeh 1989 and Morris in this volume). We present here a single wide-field image, at λ90cm, which shows all the filamentary structures in this region and show that these observations are consistent with the above hypothesis.

scholarly journals MAGNETIC FIELD CONFIGURATION AT THE GALACTIC CENTER INVESTIGATED BY WIDE-FIELD NEAR-INFRARED POLARIMETRY: TRANSITION FROM A TOROIDAL TO A POLOIDAL MAGNETIC FIELD

2010 ◽  
Vol 722 (1) ◽  
pp. L23-L27 ◽  
Author(s):  
Shogo Nishiyama ◽  
Hirofumi Hatano ◽  
Motohide Tamura ◽  
Noriyuki Matsunaga ◽  
Tatsuhito Yoshikawa ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Near Infrared ◽  
Galactic Center ◽  
Field Configuration ◽  
Wide Field ◽  
Magnetic Field Configuration ◽  
Poloidal Magnetic Field

scholarly journals The Large-Scale Magnetic Field Structure Near the Galactic Centre

1990 ◽  
Vol 140 ◽  
pp. 369-372
Author(s):  
Wolfgang Reich
Keyword(s):  
Magnetic Field ◽  
High Frequency ◽  
Large Scale ◽  
Field Structure ◽  
Galactic Centre ◽  
Poloidal Magnetic Field ◽  
Magnetic Field Structure ◽  
Large Scale Magnetic Field ◽  
Centre Region ◽  
The Magnetic Field

High frequency polarization observations reveal the existence of a poloidal magnetic field structure in the Galactic Centre region on scales of about 200 pc. At lower frequencies large non–thermal spurs are seen tracing the magnetic field up to kpc distances from the Galactic Centre.

scholarly journals On the dynamical interaction between overshooting convection and an underlying dipole magnetic field – I. The non-dynamo regime

2021 ◽  
Vol 503 (1) ◽  
pp. 362-375
Author(s):  
L Korre ◽  
NH Brummell ◽  
P Garaud ◽  
C Guervilly
Keyword(s):  
Magnetic Field ◽  
Turbulent Diffusion ◽  
Large Scale ◽  
Molecular Diffusion ◽  
Mean Field ◽  
Stable Region ◽  
Turbulent Regime ◽  
Poloidal Magnetic Field ◽  
Dynamical Interaction ◽  
Large Scale Field

ABSTRACT Motivated by the dynamics in the deep interiors of many stars, we study the interaction between overshooting convection and the large-scale poloidal fields residing in radiative zones. We have run a suite of 3D Boussinesq numerical calculations in a spherical shell that consists of a convection zone with an underlying stable region that initially compactly contains a dipole field. By varying the strength of the convective driving, we find that, in the less turbulent regime, convection acts as turbulent diffusion that removes the field faster than solely molecular diffusion would do. However, in the more turbulent regime, turbulent pumping becomes more efficient and partially counteracts turbulent diffusion, leading to a local accumulation of the field below the overshoot region. These simulations suggest that dipole fields might be confined in underlying stable regions by highly turbulent convective motions at stellar parameters. The confinement is of large-scale field in an average sense and we show that it is reasonably modelled by mean-field ideas. Our findings are particularly interesting for certain models of the Sun, which require a large-scale, poloidal magnetic field to be confined in the solar radiative zone in order to explain simultaneously the uniform rotation of the latter and the thinness of the solar tachocline.

MAGNETIC FIELD DEPENDENCE OF CRITICAL CURRENTS IN SUPERCONDUCTING POLYCRYSTALS

1992 ◽  
Vol 06 (03) ◽  
pp. 161-169 ◽  
Author(s):  
K.I. KUGEL ◽  
T. YU. LISOVSKAYA ◽  
R.G. MINTS
Keyword(s):  
Magnetic Field ◽  
Magnetic Field Dependence ◽  
Asymptotic Form ◽  
Critical Currents ◽  
Transport Current ◽  
Wide Field ◽  
London Penetration Depth ◽  
Field Range ◽  
Crystallographic Axes ◽  
The Magnetic Field

We study the dependence of critical current j c on magnetic field H in superconducting polycrystals which are considered as systems of superconducting crystallites (isotropic or anisotropic) with Josephson contacts between them. Isotropy or anisotropy of contacts depends on the orientation of their crystallographic axes relatively to edges of contact planes. It is shown that for a system of randomly oriented isotropic contacts, the dependence j c (H) in a relatively wide field range has the asymptotic form j c ~( ln H)/H2. This differs drastically from j c (H) for single contacts. Anisotropy effects due to large differences in London penetration depth λ values corresponding to external magnetic field directed along different axes are analyzed in detail. It is shown that for uniaxal crystals with λ1=λ2≪λ3, this anisotropy leads to the relation [Formula: see text] for chaotic orientation of crystallites. The form of j c (H) curves for two different orientations of the magnetic field relatively to the transport current through the sample is found.

scholarly journals Generation of shocked hot regions in black hole magnetosphere

2006 ◽  
Vol 2 (S238) ◽  
pp. 367-368
Author(s):  
Keigo Fukumura ◽  
Masaaki Takahashi ◽  
Sachiko Tsuruta
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Event Horizon ◽  
Accretion Disk ◽  
High Energy ◽  
Magnetized Plasma ◽  
Shock Formation ◽  
Poloidal Magnetic Field ◽  
High Energy Radiation ◽  
Plausible Mechanism

AbstractWe study magnetohydrodynamic (MHD) standing shocks in ingoing plasmas in a black hole (BH) magnetosphere. We find that low or mid latitude (non-equatorial) standing MHD shocks are both physically possible, creating very hot and/or magnetized plasma regions close to the event horizon. We also investigate the effects of the poloidal magnetic field and the BH spin on the properties of shocks and show that both effects can quantitatively affect the MHD shock solutions. MHD shock formation can be a plausible mechanism for creating high energy radiation region above an accretion disk in AGNs.

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.

Calculation of the Poloidal Magnetic Field Configuration for the J-TEXT Tokamak

2010 ◽  
Vol 20 (3) ◽  
pp. 1840-1843 ◽  
Author(s):  
Yong He ◽  
Zhoujun Yang ◽  
Weigang Ba ◽  
Xiaoqing Zhang ◽  
Ge Zhuang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Configuration ◽  
Magnetic Field Configuration ◽  
Poloidal Magnetic Field
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