scholarly journals MHD and Plasma Interpretation of a Prominence Eruption Observed by SOHO

1998 ◽  
Vol 167 ◽  
pp. 294-301 ◽  
Author(s):  
P.C.H. Martens
Keyword(s):  
Magnetic Field ◽  
Standard Model ◽  
Flux Tube ◽  
High Velocity ◽  
Weak Magnetic Field ◽  
Plasma Temperature ◽  
Magnetic Field Topology ◽  
The Standard Model ◽  
Mhd Stability ◽  
The Magnetic Field

AbstractData on the May 1, 1996 prominence eruption, jointly observed by CDS, SUMER, and EIT, aboard SOHO, Yohkoh-SXT, and Kitt Peak and Meudon observatories are analyzed to obtain information on the plasma temperature, density, and velocities, as well as the magnetic field topology and strength. It is found that the ‘standard’ model of an erupting helical flux tube probably applies, although questions arise on the MHD stability of the prominence flux tube. The prominence is observed to remain relatively cool during its eruption (≤ 5 × 105K), while the density and velocity vary considerably on scales down to the limit of resolution. It is found that the high density, high velocity plasma blobs can be contained by the relatively weak magnetic field, as is indeed observed.

scholarly journals Side-conditioned axisymmetric equilibria with incompressible flows

2008 ◽  
Vol 74 (3) ◽  
pp. 327-344 ◽  
Author(s):  
G. N. THROUMOULOPOULOS ◽  
H. TASSO ◽  
G. POULIPOULIS
Keyword(s):  
Magnetic Field ◽  
Incompressible Flows ◽  
Plasma Temperature ◽  
Magnetic Axis ◽  
Toroidal Shell ◽  
Initial Value ◽  
Magnetic Field Topology ◽  
Equilibrium Configurations ◽  
Magnetic Surfaces ◽  
The Magnetic Field

AbstractAxisymmetric equilibria with incompressible flows of arbitrary direction are studied in the framework of magnetohydrodynamics under a variety of physically relevant side conditions consisting, for example, in that the plasma temperature or the magnetic field modulus are uniform on magnetic surfaces. To this end a set of pertinent nonlinear ordinary differential equations (ODEs) are transformed to quasilinear ODEs and the respective initial value problem is solved numerically with appropriately determined initial values near the magnetic axis. Several equilibrium configurations are then constructed surface by surface. It turns out that in addition to the usual configurations with a magnetic axis, the non-field aligned flow results to novel toroidal shell equilibria in which the plasma is confined within a couple of magnetic surfaces. In addition, the flow affects the elongation and triangularity of the magnetic surfaces and opens up the possibility of changing the magnetic field topology by creating double toroidal shell-like configurations.

Dynamics of a disc in a nematic liquid crystal

Soft Matter ◽  
2016 ◽  
Vol 12 (4) ◽  
pp. 1279-1294 ◽  
Author(s):  
Alena Antipova ◽  
Colin Denniston
Keyword(s):  
Magnetic Field ◽  
Liquid Crystal ◽  
Numerical Simulations ◽  
Nematic Liquid Crystal ◽  
Weak Magnetic Field ◽  
Angular Speed ◽  
The Magnetic Field

We explain the motion of a micron-sized ferromagnetic disc immersed in a nematic liquid crystal under the action of a weak magnetic field using numerical simulations. We show that the disc's behaviour can be controlled by the angular speed of the magnetic field and its magnitude.

scholarly journals THE ENERGY EIGENVALUES OF THE TWO DIMENSIONAL HYDROGEN ATOM IN A MAGNETIC FIELD

2006 ◽  
Vol 15 (06) ◽  
pp. 1263-1271 ◽  
Author(s):  
A. SOYLU ◽  
O. BAYRAK ◽  
I. BOZTOSUN
Keyword(s):  
Magnetic Field ◽  
Hydrogen Atom ◽  
Iteration Method ◽  
Weak Magnetic Field ◽  
The Other ◽  
Asymptotic Iteration Method ◽  
Iterative Approach ◽  
Two Dimensional ◽  
Energy Eigenvalues ◽  
The Magnetic Field

In this paper, the energy eigenvalues of the two dimensional hydrogen atom are presented for the arbitrary Larmor frequencies by using the asymptotic iteration method. We first show the energy eigenvalues for the case with no magnetic field analytically, and then we obtain the energy eigenvalues for the strong and weak magnetic field cases within an iterative approach for n=2-10 and m=0-1 states for several different arbitrary Larmor frequencies. The effect of the magnetic field on the energy eigenvalues is determined precisely. The results are in excellent agreement with the findings of the other methods and our method works for the cases where the others fail.

Why only a small fraction of quasars are radio loud?

2018 ◽  
Vol 14 (S342) ◽  
pp. 201-204
Author(s):  
Xinwu Cao
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Angular Momentum ◽  
Angular Velocity ◽  
Strong Magnetic Field ◽  
Weak Magnetic Field ◽  
Thin Disk ◽  
Relativistic Jets ◽  
Jet Formation ◽  
The Magnetic Field

AbstractIt is still a mystery why only a small fraction of quasars contain relativistic jets. A strong magnetic field is a necessary ingredient for jet formation. Gas falls from the Bondi radius RB nearly freely to the circularization radius Rc, and a thin accretion disk is formed within Rc We suggest that the external weak magnetic field threading interstellar medium is substantially enhanced in this region, and the magnetic field at Rc can be sufficiently strong to drive outflows from the disk if the angular velocity of the gas is low at RB. In this case, the magnetic field is efficiently dragged in the disk, because most angular momentum of the disk is removed by the outflows that lead to a significantly high radial velocity. The strong magnetic field formed in this way may accelerate jets in the region near the black hole, either by the Blandford-Payne or/and Blandford-Znajek mechanisms. If the angular velocity of the circumnuclear gas is low, the field advection in the thin disk is inefficient, and it will appear as a radio-quiet (RQ) quasar.

scholarly journals PERIODIC RADIO EMISSION FROM THE M7 DWARF 2MASS J13142039+1320011: IMPLICATIONS FOR THE MAGNETIC FIELD TOPOLOGY

2011 ◽  
Vol 741 (1) ◽  
pp. 27 ◽  
Author(s):  
M. McLean ◽  
E. Berger ◽  
J. Irwin ◽  
J. Forbrich ◽  
A. Reiners
Keyword(s):  
Magnetic Field ◽  
Radio Emission ◽  
Magnetic Field Topology ◽  
The Magnetic Field

scholarly journals On the magnetic field topology in reconnection region

2018 ◽  
Vol 1100 ◽  
pp. 012007
Author(s):  
G Consolini ◽  
V Quattrociocchi ◽  
M F Marcucci
Keyword(s):  
Magnetic Field ◽  
Magnetic Field Topology ◽  
Reconnection Region ◽  
The Magnetic Field

scholarly journals On the stability of a general magnetic field topology in stellar radiative zones

2019 ◽  
Vol 82 ◽  
pp. 365-371
Author(s):  
K. Augustson ◽  
S. Mathis ◽  
A. Strugarek
Keyword(s):  
Magnetic Field ◽  
Global Change ◽  
Magnetic Fields ◽  
Potential Energy ◽  
Massive Stars ◽  
Spherical Geometry ◽  
Stable Region ◽  
Magnetic Field Topology ◽  
The Stability ◽  
The Magnetic Field

This paper provides a brief overview of the formation of stellar fossil magnetic fields and what potential instabilities may occur given certain configurations of the magnetic field. One such instability is the purely magnetic Tayler instability, which can occur for poloidal, toroidal, and mixed poloidal-toroidal axisymmetric magnetic field configurations. However, most of the magnetic field configurations observed at the surface of massive stars are non-axisymmetric. Thus, extending earlier studies in spherical geometry, we introduce a formulation for the global change in the potential energy contained in a convectively-stable region for both axisymmetric and non-axisymmetric magnetic fields.

Influence of the Magnetic Field Topology on Hall Thruster Discharge Channel Wall Erosion

2012 ◽  
Vol 22 (3) ◽  
pp. 4904105-4904105 ◽  
Author(s):  
Chang Liu ◽  
Zuo Gu ◽  
Kan Xie ◽  
Yunkui Sun ◽  
Haibin Tang
Keyword(s):  
Magnetic Field ◽  
Channel Wall ◽  
Discharge Channel ◽  
Hall Thruster ◽  
Magnetic Field Topology ◽  
The Magnetic Field
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