Axialsymmetrische Lösungen der magnetohydrostatischen Gleichung mit Oberflächenströmen II

1958 ◽  
Vol 13 (7) ◽  
pp. 493-498 ◽  
Author(s):  
K. Jörgens
Keyword(s):  
Magnetic Field ◽  
Cross Section ◽  
Circular Cross Section ◽  
Arbitrary Cross Section ◽  
Axially Symmetric ◽  
Equilibrium Configurations ◽  
Circular Case ◽  
Axis Of Symmetry ◽  
Hydrodynamic Equilibrium ◽  
The Magnetic Field

Axially symmetric magneto-hydrodynamic equilibrium configurations are considered where the plasma is contained in a torus of arbitrary cross-section and electric currents flow in the surface of the plasma only. It is shown that the magnetic field is uniquely determined by the values of the total current in azimuthal and in meridional direction respectively and by the gas pressure. A method is given to compute the location of discontinuities of the magnetic field outside of the torus. The singularities are found explicitly in the case of elliptic or circular cross-section. In the circular case only the magnetic field is regular everywhere outside except on the axis of symmetry.

The evolution of magnetic flux ropes in sheared plasma flows

2000 ◽  
Vol 64 (1) ◽  
pp. 41-55 ◽  
Author(s):  
J. M. SCHMIDT ◽  
P. J. CARGILL
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Shear Layer ◽  
Cross Section ◽  
Circular Cross Section ◽  
Flux Rope ◽  
Plasma Pressure ◽  
Magnetic Flux Ropes ◽  
Flux Ropes ◽  
The Magnetic Field

The evolution of magnetic flux ropes in a sheared plasma flow is investigated. When the magnetic field outside the flux rope lies parallel to the axis of the flux rope, a flux rope of circular cross-section, whose centre is located at the midpoint of the shear layer, has its shape distorted, but remains in the shear layer. Small displacements of the flux-rope centre above or below the midpoint of the shear layer lead to the flux-rope being expelled from the shear layer. This motion arises because small asymmetries in the plasma pressure around the flux-rope boundary leads to a force that forces the flux rope into a region of uniform flow. When the magnetic field outside the flux rope lies in a plane perpendicular to the flux-rope axis, the flux rope and external magnetic field reconnect with each other, leading to the destruction of the flux rope.

Excitation of a conducting cylinder by an axial electric dipole

1968 ◽  
Vol 46 (3) ◽  
pp. 211-219
Author(s):  
L. Shafai
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Field ◽  
Cross Section ◽  
Electric Dipole ◽  
Circular Cross Section ◽  
Conducting Cylinder ◽  
Infinite Integral ◽  
The Magnetic Field

The electromagnetic field of an axial electric dipole near a perfectly conducting cylinder of circular cross section is expressed in terms of an infinite integral. For the magnetic field on the surface of the cylinder, the integral is evaluated analytically for cylinders of small and large radii and numerically for cylinders of moderate radii.

Dynamic Self-Assembly in Confined Micro-Domains

2004 ◽  
Author(s):  
Dong Liu ◽  
Martin Maxey ◽  
George Karniadakis
Keyword(s):  
Magnetic Field ◽  
Cross Section ◽  
Self Assembly ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Self Assembled ◽  
Paramagnetic Beads ◽  
Exciting Possibility ◽  
The Magnetic Field

We simulate dynamic self-assembly of paramagnetic beads in domains of rectangular, triangular and circular cross-section. We demonstrate that depending on the magnetic field, the number of microparticles, and the shape of microdomain, different self-assembled structures can be produced. This provides an exciting possibility for making reconfigurable multi-functional microdevices, and may also suggest new protocols for fabricating three-dimensional microsystems and nanosystems.

Axialsymmetrische Lösungen der magnetohydrostatischen Gleichung mit Oberflächenströmen

1957 ◽  
Vol 12 (10) ◽  
pp. 826-832
Author(s):  
L. Biermann ◽  
K. Hain ◽  
K. Jörgens ◽  
R. Lust
Keyword(s):  
Magnetic Field ◽  
Boundary Conditions ◽  
Axial Symmetry ◽  
Circular Cross Section ◽  
Homogeneous Field ◽  
Electric Currents ◽  
Azimuthal Component ◽  
Axis Of Symmetry ◽  
The Given ◽  
The Magnetic Field

Es werden axialsymmetrische Lösungen der magnetohydrostatischen Gleichung betrachtet, bei denen das Gas einen Torus erfüllt, dessen Querschnitt im allgemeinen kreisförmig angenommen wird. Zur Vereinfachung wird angenommen, daß die elektrischen Ströme nur an der Oberfläche fließen. Für den Fall, daß diese Ströme gegeben sind, wird ein Verfahren angegeben, mit dem das äußere Magnetfeld berechnet werden kann, welches zusammen mit dem durch den gegebenen Strom erzeugten Feld die Grenzbedingungen erfüllt. Dies Verfahren wird für den Fall rein azimutaler Ströme mit einer Näherungsmethode und dann exakt durchgeführt. In erster Näherung genügt die Überlagerung eines homogenen Feldes parallel zur Symmetrieachse des Torus. Für den Fall gegebener meridionaler Ströme zeigt sich, daß die Randbedingungen nur durch Überlagerung eines zusätzlichen azimutalen Stromes erfüllbar sind, zusammen mit einem geeigneten meridionalen äußeren Magnetfeld. Im axialsymmetrischen Fall ist also stets mindestens eine azimutale Stromkomponente erforderlich.It is proposed to consider solutions of the magnetohydrostatic equation of axial symmetry in which the plasma is contained in a torus with circular cross-section. For mathematical simplification it is furthermore assumed, that the electric currents flow exclusively at the surface of the plasma. For the case, that these currents are assumed to be given, a method is outlined by which it is possible to calculate the exterior magnetic field which together with the magnetic field produced by the given currents, satisfies the boundary conditions at the surface. This procedure is carried through for the case of purely azimuthal electric currents, first by an approximate method, then by an exact method. To a first approximation it is sufficient to superpose an homogeneous field parallel to the axis of symmetry. For the case that the given currents are in a meridional planes, it is seen, that the boundary conditions can be satisfied only by the superposition of an additional current together with a suitable meridional exterior magnetic field. Therefore in the case of axial symmetry at least one azimuthal component of the electric current is necessary.

Improvement of magnetic probe measurements

1970 ◽  
Vol 48 (11) ◽  
pp. 1370-1377
Author(s):  
F. L. Curzon ◽  
J. Pachner Jr. ◽  
Y. K. S. Tam
Keyword(s):  
Magnetic Field ◽  
Cross Section ◽  
Current Flow ◽  
Circular Cross Section ◽  
Single Coil ◽  
Fractional Error ◽  
Z Pinch ◽  
Perturbed Magnetic Field ◽  
The Magnetic Field ◽  
Probe Measurements

By considering the current flow around a probe guide of a circular cross section, it is shown that the perturbed magnetic field can be partially "corrected" with a three coil probe. The theory has been tested in a coaxial cylindrical geometry, an analogue of a Z-pinch discharge. The spatial resolution l of the three coil probe is roughly one half of the probe guide radius, a. For current distributions which vary slowly with distance (scale length, λ) it is shown that the fractional error in the magnetic field is ~ 0.2(l/λ)2. For a single coil probe the error is at least four times as large.

scholarly journals THREE-BODY PHOTODISINTEGRATION OF 4He NUCLEUS BY LINEARLY POLARIZED PHOTONS

2019 ◽  
pp. 11-15
Author(s):  
A.A. Peretiatko ◽  
R.T. Murtazin ◽  
A.F. Khodyachikh
Keyword(s):  
Magnetic Field ◽  
Cross Section ◽  
Production Cross ◽  
Reaction Products ◽  
Azimuthal Distribution ◽  
Proton Production ◽  
Linearly Polarized ◽  
Three Body ◽  
Polarized Photons ◽  
The Magnetic Field

Experimental data are reported from studies of the reaction 4He(γ, pn)d through the use of the streamer chamber placed in the magnetic field and exposed to a linearly polarized photon beam from the electron linac LUE-2000. A structure has been revealed in the momentum distribution of deuterons. Studies were made into the effects of nucleon-deuteron correlation. The azimuthal distribution of reaction products and the asymmetry of proton production cross-section were measured. The obtained data were analyzed in the framework of the quasideuteron model.

Sign in / Sign up

Export Citation Format

Share Document