scholarly journals Singular domains of the low-frequency cold-plasma wave equation

1988 ◽  
Vol 30 (9) ◽  
pp. 1195-1199 ◽  
Author(s):  
K Appert
Keyword(s):  
Wave Equation ◽  
Plasma Wave ◽  
Cold Plasma ◽  
Low Frequency ◽  
Singular Domains

On the existence of compressional MHD oscillations in an inhomogeneous magnetoplasma

1990 ◽  
Vol 44 (2) ◽  
pp. 361-375 ◽  
Author(s):  
Andrew N. Wright
Keyword(s):  
Magnetic Field ◽  
Wave Equation ◽  
Density Distribution ◽  
Cold Plasma ◽  
Wave Equations ◽  
Perturbation Field ◽  
Plasma Density Distribution ◽  
Background Magnetic Field ◽  
Transverse Fields ◽  
The Magnetic Field

In a cold plasma the wave equation for solely compressional magnetic field perturbations appears to decouple in any surface orthogonal to the background magnetic field. However, the compressional fields in any two of these surfaces are related to each other by the condition that the perturbation field b be divergence-free. Hence the wave equations in these surfaces are not truly decoupled from one another. If the two solutions happen to be ‘matched’ (i.e. V.b = 0) then the medium may execute a solely compressional oscillation. If the two solutions are unmatched then transverse fields must evolve. We consider two classes of compressional solutions and derive a set of criteria for when the medium will be able to support pure compressional field oscillations. These criteria relate to the geometry of the magnetic field and the plasma density distribution. We present the conditions in such a manner that it is easy to see if a given magnetoplasma is able to executive either of the compressional solutions we investigate.

scholarly journals COMPLEX WAVE NUMBERS IN THE VICINITY OF THE SCHWARZSCHILD EVENT HORIZON

2008 ◽  
Vol 23 (09) ◽  
pp. 1417-1433 ◽  
Author(s):  
M. SHARIF ◽  
UMBER SHEIKH
Keyword(s):  
Event Horizon ◽  
Plasma Wave ◽  
Cold Plasma ◽  
Dispersion Relations ◽  
Wave Numbers ◽  
Complex Wave ◽  
And Behavior ◽  
Wave Properties

This paper is devoted to investigate the cold plasma wave properties outside the event horizon of the Schwarzschild planar analogue. The dispersion relations are obtained from the corresponding Fourier analyzed equations for nonrotating and rotating, nonmagnetized and magnetized backgrounds. These dispersion relations provide complex wave numbers. The wave numbers are shown in graphs to discuss the nature and behavior of waves and the properties of plasma lying in the vicinity of the Schwarzschild event horizon.

scholarly journals Morawetz estimates for the wave equation at low frequency

2012 ◽  
Vol 355 (4) ◽  
pp. 1221-1254 ◽  
Author(s):  
András Vasy ◽  
Jared Wunsch
Keyword(s):  
Wave Equation ◽  
Low Frequency

Researching on Characteristics of Rayleigh Waves

2014 ◽  
Vol 721 ◽  
pp. 472-475
Author(s):  
Xu Fang Zhu ◽  
Bing Yan
Keyword(s):  
Wave Equation ◽  
Rayleigh Wave ◽  
Dispersion Equation ◽  
Rayleigh Waves ◽  
Low Frequency ◽  
Secondary Wave ◽  
Reflected Wave ◽  
Strong Energy ◽  
Geological Information ◽  
Interface Distance

Rayleigh wave is a secondary wave characterized by low frequency and strong energy, propagating mainly along the interface of medium and rapid attenuation of energy with increase in interface distance. The same as reflected wave and refracted wave, Rayleigh wave also contain subsurface geological information. In this paper, the concept of the Rayleigh wave, wave equation, dispersion equation, the frequency bulk characteristics and the application of the actual data are used to indicate the characteristics of Rayleigh wave and its application.

A Perturbation Method for Low-Frequency Fluid-Structure Interaction Problems

1973 ◽  
Vol 40 (2) ◽  
pp. 388-394 ◽  
Author(s):  
Y. K. Lou
Keyword(s):  
Wave Equation ◽  
Perturbation Method ◽  
Electromagnetic Scattering ◽  
Perturbation Methods ◽  
Separation Of Variables ◽  
Fluid Structure Interaction ◽  
Low Frequency ◽  
Approximate Solutions ◽  
Fluid Structure ◽  
Structure Interaction

Perturbation methods have been used for electromagnetic scattering and diffraction problems in recent years. A similar method suitable for low-frequency fluid-structure interaction problems is presented. The essence of the method lies in the fact that approximate solutions for fluid-structure interaction problems can be obtained from a set of Poisson’s equations, rather than from the reduced wave equation. The method is particularly useful for those problems where the Poisson’s equation may be solved by the method of separation of variables while the reduced wave equation cannot. As an illustrative example, the vibrations of a submerged spherical shell is studied using the perturbation method and the accuracy of the method is demonstrated.

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