The magnetic flux problem and ambipolar diffusion during star formation - One-dimensional collapse. II - Results

1985 ◽  
Vol 291 ◽  
pp. 772 ◽  
Author(s):  
T. Ch. Mouschovias ◽  
E. V. Paleologou ◽  
R. A. Fiedler
Keyword(s):  
Star Formation ◽  
Magnetic Flux ◽  
Ambipolar Diffusion ◽  
One Dimensional

Untersuchung des Druckaufbaus einer stationären, magnetfeldstabilisierten Helium-Entladung mit Hilfe magnetischer Messungen

1967 ◽  
Vol 22 (10) ◽  
pp. 1599-1612 ◽  
Author(s):  
Otto Klüber
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Plasma Column ◽  
Ambipolar Diffusion ◽  
Nernst Effect ◽  
Thermomagnetic Effect ◽  
Field Coil ◽  
Neutral Gas ◽  
Ring Currents ◽  
The Magnetic Field

A stationary discharge is produced bya current flowing parallel to the magnetic field ofa cylindrical coil. In the region where the field is homogeneous the pressure in the plasma column is much higher than that in the surrounding neutral gas. This is mainly caused by diamagnetic ring currents, as is shown by measuring the magnetic flux due to these currents. Two effects are primarily responsible for the ring currents in this region: The already known effect of the ambipolar diffusion across the magnetic field anda thermomagnetic effect, called NERNST effect, whose influence on the pressure build-up ofa plasma has not been investigated hitherto. Other phenomena causing ring currents occur in the plasma near the coil ends and outside the field coil.

Magnetic Flux Transport in the ISM through Turbulent Ambipolar Diffusion

2004 ◽  
pp. 45-51
Author(s):  
Fabian Heitsch ◽  
Ellen G. Zweibel ◽  
Adrianne D. Slyz ◽  
Julien E. G. Devriendt
Keyword(s):  
Magnetic Flux ◽  
Ambipolar Diffusion ◽  
Flux Transport

QUANTUM WAVEGUIDE THEORY FOR TRIPLY CONNECTED AHARONOV–BOHM RINGS

1996 ◽  
Vol 10 (06) ◽  
pp. 701-712 ◽  
Author(s):  
CHANG-MO RYU ◽  
SAM YOUNG CHO ◽  
MINCHEOL SHIN ◽  
KYOUNG WAN PARK ◽  
SEONGJAE LEE ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Wave Vector ◽  
Quantum Interference ◽  
Transmission Probability ◽  
Interference Effects ◽  
Quantum Waveguide ◽  
One Dimensional ◽  
Waveguide Theory ◽  
Aharonov Bohm ◽  
Transmission And Reflection

Quantum interference effects for a mesoscopic loop with three leads are investigated by using a one-dimensional quantum waveguide theory. The transmission and reflection probabilities are analytically obtained in terms of the magnetic flux, arm length, and wave vector. Oscillation of the magnetoconductance is explicitly demonstrated. Magnetoconductance is found to be sharply peaked for certain localized values of flux and kl. In addition, it is noticed that the periodicity of the transmission probability with respect to kl depends more sensitively on the lead position, compared to the case of the two-lead loop.

scholarly journals A nonlinear equation for ionic diffusion in a strong binary electrolyte

2010 ◽  
Vol 466 (2119) ◽  
pp. 2145-2154 ◽  
Author(s):  
Sandip Ghosal ◽  
Zhen Chen
Keyword(s):  
Poisson Equation ◽  
Characteristic Length ◽  
Nonlinear Partial Differential Equation ◽  
Debye Length ◽  
Ambipolar Diffusion ◽  
One Dimensional ◽  
The Poisson Equation ◽  
Local Charge ◽  
Asymptotic Parameter ◽  
The One

The problem of the one-dimensional electro-diffusion of ions in a strong binary electrolyte is considered. The mathematical description, known as the Poisson–Nernst–Planck (PNP) system, consists of a diffusion equation for each species augmented by transport owing to a self-consistent electrostatic field determined by the Poisson equation. This description is also relevant to other important problems in physics, such as electron and hole diffusion across semiconductor junctions and the diffusion of ions in plasmas. If concentrations do not vary appreciably over distances of the order of the Debye length, the Poisson equation can be replaced by the condition of local charge neutrality first introduced by Planck. It can then be shown that both species diffuse at the same rate with a common diffusivity that is intermediate between that of the slow and fast species (ambipolar diffusion). Here, we derive a more general theory by exploiting the ratio of the Debye length to a characteristic length scale as a small asymptotic parameter. It is shown that the concentration of either species may be described by a nonlinear partial differential equation that provides a better approximation than the classical linear equation for ambipolar diffusion, but reduces to it in the appropriate limit.

scholarly journals Quasistatic Contraction of Magnetic Protostars due to Magnetic Flux Leakage

1981 ◽  
Vol 93 ◽  
pp. 63-64
Author(s):  
Takenori Nakano
Keyword(s):  
Magnetic Flux ◽  
Ambipolar Diffusion ◽  
Magnetic Flux Leakage ◽  
Magnetic Tube ◽  
Plasma Drift ◽  
Flux Leakage ◽  
New Distribution

A protostar with sufficient magnetic flux can be in quasistatic equilibrium. The structure at the time t of such an axisymmetric protostar immersed in a medium of finite pressure is determined when the mass m(ϕ, t) in each axisymmetric magnetic tube with the flux ϕ is given. A new distribution m(ϕ, t+δt) is found by calculating the amount of matter which crosses the surface of the magnetic tube ϕ in a time δt due to plasma drift (ambipolar diffusion), and then the structure at t+δt is determined. By repeating this procedure we can follow the quasistatic contraction of a protostar. Here we take into account the effect of charged grains in addition to ions upon the plasma drift.

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