scholarly journals A Helical Magnetic Field Model of the Jets

1987 ◽  
Vol 115 ◽  
pp. 381-383
Author(s):  
T. Maruyama ◽  
M. Fujimoto
Keyword(s):  
Magnetic Field ◽  
Active Galactic Nuclei ◽  
Lorentz Force ◽  
Field Model ◽  
Galactic Nuclei ◽  
Molecular Gas ◽  
Magnetic Field Model ◽  
Helical Magnetic Field ◽  
Jet Axis

A hydromagnetic model is presented for the bipolar flow of molecular gas from newborn stars and for the radio jet emerging out of active galactic nuclei. We assume a tightly-twisted helical magnetic field in the jet, which can collimate and accelerate the gas along the jet axis. The Lorentz force is also shown to rotate the gas around it.

scholarly journals Discovery of Helical Magnetic Fields in AGN, and CME and Ejection of Large-Scale Magnetic Fields from AGN

2003 ◽  
Vol 214 ◽  
pp. 303-308
Author(s):  
Han-Shu Chu ◽  
L. B. Baath ◽  
Fu-Jun Zhang ◽  
R. E. Spencer
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Active Galactic Nuclei ◽  
Large Scale ◽  
Direct Detection ◽  
Galactic Nuclei ◽  
Crucial Importance ◽  
Important Ingredient ◽  
Celestial Bodies ◽  
Helical Magnetic Field

Magnetic Fields are the crucial and most important ingredient involved in the processes of various violent activities in Active Galactic Nuclei and other celestial bodies. The generally accepted 2-sided symmetric-jets model of active galactic nuclei (AGN) does not include the magnetic fields. We present here the first direct detection of helical magnetic field in AGN, and the first direct detection of ejection of large scale magnetic fields from AGN. (CME) 2. The annular (helical) magnetic field is responsible for the collimation of the jet (through Pinch Effect) and may be of crucial importance for extraction of black hole rotational energy. 3. The CMEs are responsible for sporadic ejection of jet components in AGN, while the general accepted 2-sided jets pertain to the quiescent Jets. 4. Observations show that the CME with Asymmetric Jets can explain many phenomena and much of the morphological diversities in AGN.

scholarly journals Long-Lived Positronium and AGN Jets

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
John T. Giblin ◽  
Janine Shertzer
Keyword(s):  
Magnetic Field ◽  
Black Holes ◽  
Active Galactic Nuclei ◽  
Accretion Disks ◽  
Bound States ◽  
Galactic Nuclei ◽  
Stable States ◽  
Electrons And Positrons ◽  
Field Lines ◽  
Helical Magnetic Field

We suggest that stable states of positronium might exist in the jets of active galactic nuclei (AGN). Electrons and positrons are created near the accretion disks of supermassive black holes at the centers of AGN and are accelerated along magnetic field lines while within the Alfvèn radius. The conditions in this region are ideal for the creation of bound states of positronium which are stable against annihilation. Traveling at relativistic speeds along the jet, the helical magnetic field enables the atoms to survive for great distances.

scholarly journals A case study of the plasma in the magneto-sheath using the numerical magnetosheath-magnetosphere model and THEMIS measure-ments

2018 ◽  
Vol 145 ◽  
pp. 03004
Author(s):  
Polya Dobreva ◽  
Olga Nitcheva ◽  
Monio Kartalev
Keyword(s):  
Magnetic Field ◽  
Field Model ◽  
Specific Aspect ◽  
Plasma Parameters ◽  
Ion Density ◽  
Magnetic Field Model ◽  
Wind Spacecraft ◽  
The Mean ◽  
The Magnetic Field

This paper presents a case study of the plasma parameters in the magnetosheath, based on THEMIS measurements. As a theoretical tool we apply the self-consistent magnetosheath-magnetosphere model. A specific aspect of the model is that the positions of the bow shock and the magnetopause are self-consistently determined. In the magnetosheath the distribution of the velocity, density and temperature is calculated, based on the gas-dynamic theory. The magnetosphere module allows for the calculation of the magnetopause currents, confining the magnetic field into an arbitrary non-axisymmetric magnetopause. The variant of the Tsyganenko magnetic field model is applied as an internal magnetic field model. As solar wind monitor we use measurements from the WIND spacecraft. The results show that the model quite well reproduces the values of the ion density and velocity in the magnetosheath. The simlicity of the model allows calulations to be perforemed on a personal computer, which is one of the mean advantages of our model.

CO2 — A Champ Magnetic Field Model

2003 ◽  
pp. 220-225 ◽  
Author(s):  
Richard Holme ◽  
Nils Olsen ◽  
Martin Rother ◽  
Hermann Lühr
Keyword(s):  
Magnetic Field ◽  
Field Model ◽  
Magnetic Field Model

By Cam: A Multipole Magnetic Field Model

1995 ◽  
pp. 426-426 ◽  
Author(s):  
Paul A. Mason ◽  
G. Chanmugam ◽  
I. L. Andronov ◽  
S. V. Koleskinov ◽  
E. P. Pavlenko ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Model ◽  
Magnetic Field Model

scholarly journals Retrieving lithospheric magnetisation distribution from magnetic field models

2019 ◽  
Author(s):  
V Lesur ◽  
F Vervelidou
Keyword(s):  
Magnetic Field ◽  
Cost Function ◽  
Spherical Harmonic ◽  
Field Model ◽  
Harmonic Model ◽  
Whole Process ◽  
Magnetic Field Model ◽  
The Cost ◽  
Spherical Harmonic Model ◽  
The Magnetic Field

Summary We investigate to which extent the radially averaged magnetisation of the lithosphere can be recovered from the information content of a spherical harmonic model of the generated magnetic field when combined with few simple hypotheses. The results obtained show firstly that a hypothesis of magnetisation induced by a field of internal origin, even over a localised area, is not sufficient to recover uniquely the radially averaged magnetisation and, secondly, that this magnetisation can be recovered when a constant magnetisation direction is assumed. An algorithm to recover the magnetisation direction and distribution is then described and tested over a synthetic example. It requires to introduce a cost function that vanishes when estimated in a system of coordinates with its Z axis aligned with the magnetisation direction. Failing to find a vanishingly small value for the cost function is an indication that a constant magnetisation direction is not a valid hypothesis for the studied magnetic field model. The range of magnetisation directions that are compatible with the magnetic field model and a given noise level, can also be estimated. The whole process is illustrated by analysing a local, isolated maximum of the Martian magnetic field.

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