Stationary waves at the interface between a plasma stream and magnetic field

1982 ◽  
Vol 28 (1) ◽  
pp. 13-17 ◽  
Author(s):  
Bhimsen K. Shivamoggi
Keyword(s):  
Magnetic Field ◽  
Plasma Stream ◽  
Stationary Waves ◽  
Transform Method ◽  
Magnetic Dipoles ◽  
Shallow Water Approximation ◽  
Supersonic Plasma ◽  
Gravity Effects ◽  
The Magnetic Field ◽  
Effect Of Surface

A uniformly-streaming compressible and infinitely-conducting plasma is confined by a magnetic field aligned with the stream. The system is disturbed by introducing magnetic dipoles into the field. A Fourier-transform method is used to determine the displacement of the interface between the streaming plasma and the magnetic field within the framework of a ‘shallow-water’ approximation. For the case of a subsonic plasma stream, stationary waves appear on the interface upstream of the dipoles, and it is found that (i) these stationary waves are possible only if the gravity effects on the plasma are weak enough; (ii) the effect of surface tension at the interface is to reduce the amplitude and increase the wavelength of these waves. For the case of a supersonic plasma stream, however, stationary waves at the interface are not possible.

Static magnetic fields in vacuum

2018 ◽  
Author(s):  
J. Pierrus
Keyword(s):  
Magnetic Field ◽  
Problem Solving ◽  
Magnetic Fields ◽  
Vector Potential ◽  
Scalar Potential ◽  
Multipole Expansion ◽  
Magnetic Vector Potential ◽  
Magnetic Dipoles ◽  
Static Magnetic Fields ◽  
The Magnetic Field

Wherever possible, an attempt has been made to structure this chapter along similar lines to Chapter 2 (its electrostatic counterpart). Maxwell’s magnetostatic equations are derived from Ampere’s experimental law of force. These results, along with the Biot–Savart law, are then used to determine the magnetic field B arising from various stationary current distributions. The magnetic vector potential A emerges naturally during our discussion, and it features prominently in questions throughout the remainder of this book. Also mentioned is the magnetic scalar potential. Although of lesser theoretical significance than the vector potential, the magnetic scalar potential can sometimes be an effective problem-solving device. Some examples of this are provided. This chapter concludes by making a multipole expansion of A and introducing the magnetic multipole moments of a bounded distribution of stationary currents. Several applications involving magnetic dipoles and magnetic quadrupoles are given.

The Effect of Surface Layers in Epitaxial N-Type Hg1−xCdxTe

1989 ◽  
Vol 161 ◽  
Author(s):  
K.K. Parat ◽  
N.R. Taskar ◽  
I.B. Bhat ◽  
S.K. Ghandhi
Keyword(s):  
Magnetic Field ◽  
Field Dependence ◽  
Vapor Phase ◽  
Hall Coefficient ◽  
Diagnostic Technique ◽  
Organometallic Vapor Phase Epitaxy ◽  
Surface Layers ◽  
Surface Electrons ◽  
The Magnetic Field ◽  
Effect Of Surface

ABSTRACTThe presence of low mobility surface electrons on n-Hg1−1CdxTe is generally not apparent in the temperature dependence of the Hall Coefficient (RH) or the Hall mobility (µH) of the layer. However, its influence is clearly seen in the magnetic field (B-field) dependence of RH. The B-field dependence of RH can be analyzed to extract the bulk and surface carrier concentrations and their respective mobilities.This diagnostic technique has been used for evaluating epitaxial Hg1−xCdxTe layers grown by organometallic vapor phase epitaxy (OMVPE), which have been converted to n-type by annealing in Hg overpressure. In addition, the effect of anodic sulfide passivation on the B-field dependence of Hall coefficient is also outlined.

Superconductors With Structured Surfaces: Fields and Currents

1987 ◽  
Vol 101 ◽  
Author(s):  
Z.C. Wu ◽  
Daniel A. Jelski ◽  
Thomas F. George
Keyword(s):  
Magnetic Field ◽  
The Other ◽  
Ginzburg Landau ◽  
Landau Model ◽  
Structured Surfaces ◽  
Field Parallel ◽  
First Case ◽  
The Magnetic Field ◽  
Effect Of Structure ◽  
Effect Of Surface

ABSTRACTThis paper discusses the behavior of currents and fields along a structured superconductor. First the effect of surface structure on supercurrents is investigated. Then the effect of structure on the critical nucleation field is discussed in two cases, one with the magnetic field parallel to the ripples and the other with the field parallel to the grating wavenumber. In the first case, it is found that the critical field is reduced as a function of grating height, whereas in the latter case it is increased. Finally, the relevance of this work for laser-induced chemistry above a superconducting surface is discussed. The Ginzburg-Landau model is used throughout.

Stationary waves in a bi-ion plasma transverse to the magnetic field

2001 ◽  
Vol 65 (3) ◽  
pp. 197-212 ◽  
Author(s):  
J. F. McKENZIE ◽  
K. SAUER ◽  
E. DUBININ
Keyword(s):  
Magnetic Field ◽  
Flow Direction ◽  
Heavy Ion ◽  
Mirror Image ◽  
Structure Equation ◽  
Stationary Waves ◽  
Initial Portion ◽  
Charge Neutrality ◽  
Ion Plasma ◽  
The Magnetic Field

We investigate the nature of stationary structures streaming at subfast magnetosonic speeds perpendicular to the magnetic field in a bi-ion plasma consisting of protons and a heavy ion species in which the magnetic field is frozen into the electrons, whose inertia may be neglected. The study is based on the properties of the structure equation for the system, which is derived from the equations of motion and the Maxwell equations, and therefore reflects the coupling between the two ion fluids and the electrons through the Lorentz forces and charge neutrality. The basic features of the structure equation are elucidated by making use of conservation of total momentum and charge neutrality, which provide relations between the ion speeds in the unperturbed flow direction and the electron speed. This combination of relations, which we call the momentum hodograph of the system, reveals the structure of the flow and the magnetic field in a solitary-type pulse. In particular, we find that in the initial portion of a compressive soliton, heavy ions run ahead of the electrons and the protons lag between them until a point is reached where they all once more attain the same speed, after which the protons run ahead and are accelerated whereas the heavies now lag behind the continuously decelerating electrons. The second half of the wave is a mirror image of the first portion. The strength of the compression (the amplitude of the wave) is determined from the momentum hodograph, and depends upon the initial Mach number, abundance ratio of heavies to protons and the mass ratio. The analysis is relevant to subfast flows of mass-loaded plasmas and pile-up boundaries, which appear near comets and non-magnetic planets.

Unsteady Hydromagnetic Boundary Layer in a Rotating Medium

1976 ◽  
Vol 43 (2) ◽  
pp. 205-208 ◽  
Author(s):  
P. Puri ◽  
P. K. Kulshrestha
Keyword(s):  
Magnetic Field ◽  
Porous Plate ◽  
Three Dimensional ◽  
Power Input ◽  
Transverse Magnetic ◽  
Laplace Transform Method ◽  
Transform Method ◽  
Rotating Medium ◽  
The Laplace Transform ◽  
The Magnetic Field

The three-dimensional flow of a viscous fluid in the presence of the transverse magnetic field past an infinite porous plate moving with a time-dependent velocity in a rotating medium is investigated. An exact solution is found by using the Laplace transform method. The order of Stokes, Ekman, and Stokes-Rayleigh layers arising in the problem are derived and the influence of the magnetic field and suction (blowing) is studied. The behavior of the drag and lateral stress on the plate is discussed and the power input required to keep the plate in motion calculated. It is also found that a normal solution exists at the resonant frequency for the problem investigated here.

Stationary surface waves in magnetohydrodynamics

1982 ◽  
Vol 27 (2) ◽  
pp. 321-325 ◽  
Author(s):  
Bhimsen K. Shivamoggi
Keyword(s):  
Magnetic Field ◽  
Fourier Transform ◽  
Gravitational Field ◽  
Surface Waves ◽  
Wave Motion ◽  
Transform Method ◽  
Fourier Transform Method ◽  
Steady Pressure ◽  
The Fourier Transform ◽  
The Magnetic Field

A uniformly-streaming, semi-infinite, incompressible, infinitely-conducting plasma subjected to a gravitational field is confined by a vacuum magnetic field aligned with the stream. The system is disturbed by introducing a source of external steady pressure acting on the interface between the plasma and the magnetic field. The resulting wave motion at the interface is studied by using the Fourier-transform method to determine the solution for the displacement of the interface.

scholarly journals Inferring possible magnetic field strength of accreting inflows in EXor-type objects from scaled laboratory experiments

2021 ◽  
Vol 648 ◽  
pp. A81
Author(s):  
K. Burdonov ◽  
R. Bonito ◽  
T. Giannini ◽  
N. Aidakina ◽  
C. Argiroffi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Stellar Surface ◽  
Plasma Stream ◽  
Plasma Gun ◽  
T Tauri ◽  
Laboratory Plasmas ◽  
Accretion Rates ◽  
The Magnetic Field ◽  
Magnetospheric Accretion

Aims. EXor-type objects are protostars that display powerful UV-optical outbursts caused by intermittent and powerful events of magnetospheric accretion. These objects are not yet well investigated and are quite difficult to characterize. Several parameters, such as plasma stream velocities, characteristic densities, and temperatures, can be retrieved from present observations. As of yet, however, there is no information about the magnetic field values and the exact underlying accretion scenario is also under discussion. Methods. We use laboratory plasmas, created by a high power laser impacting a solid target or by a plasma gun injector, and make these plasmas propagate perpendicularly to a strong external magnetic field. The propagating plasmas are found to be well scaled to the presently inferred parameters of EXor-type accretion event, thus allowing us to study the behaviour of such episodic accretion processes in scaled conditions. Results. We propose a scenario of additional matter accretion in the equatorial plane, which claims to explain the increased accretion rates of the EXor objects, supported by the experimental demonstration of effective plasma propagation across the magnetic field. In particular, our laboratory investigation allows us to determine that the field strength in the accretion stream of EXor objects, in a position intermediate between the truncation radius and the stellar surface, should be of the order of 100 G. This, in turn, suggests a field strength of a few kilogausses on the stellar surface, which is similar to values inferred from observations of classical T Tauri stars.

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