Hydromagnetic Waves

Hydromagnetic Waves PDF Author: Henry R. Radoski
Publisher:
ISBN:
Category : Electric fields
Languages : en
Pages : 40

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Book Description
Numerical solutions to the initial value problem have been obtained for the guided (toroidal) and isotropic (poloidal) electric fields of hydromagnetic waves for the asymmetric case. The cylindrical model of the inner magnetosphere has been used in which the field lines are arcs of circles and the surface of the earth is planar. The cases considered have the initial disturbance completely restricted to either the guided or isotropic field components to emphasize the effect of coupling. The development of the system has been calculated for asymmetric modes of order m = 1 to 10, corresponding to from one to ten full waves in longitude and the lowest order (n =1) field-line mode, corresponding to a half-wave along a field line. The initial isotropic (east-west) electric-field component is in an eigenstate of the symmetric or uncoupled poloidal mode. In this case, when the coupling is reduced to zero, the isotropic electric field simply oscillates harmonically. The initial guided (north-south) electric-field component is defined to increase radially and towards higher latitudes. As a check on the numerical solutions, the total energy of the system is continually calculated and compared with the initial energy. Although no damping is included in the problem, the poloidal-mode energy decays with time, as has been shown theoretically. The toroidal mode reaches maximum amplitude in regions of relatively narrow latitudinal extent. The large spatial variation of the magnetic field in these resonance regions must be associated with large field aligned currents. (Author).

Hydromagnetic Waves

Hydromagnetic Waves PDF Author: Henry R. Radoski
Publisher:
ISBN:
Category : Electric fields
Languages : en
Pages : 40

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Book Description
Numerical solutions to the initial value problem have been obtained for the guided (toroidal) and isotropic (poloidal) electric fields of hydromagnetic waves for the asymmetric case. The cylindrical model of the inner magnetosphere has been used in which the field lines are arcs of circles and the surface of the earth is planar. The cases considered have the initial disturbance completely restricted to either the guided or isotropic field components to emphasize the effect of coupling. The development of the system has been calculated for asymmetric modes of order m = 1 to 10, corresponding to from one to ten full waves in longitude and the lowest order (n =1) field-line mode, corresponding to a half-wave along a field line. The initial isotropic (east-west) electric-field component is in an eigenstate of the symmetric or uncoupled poloidal mode. In this case, when the coupling is reduced to zero, the isotropic electric field simply oscillates harmonically. The initial guided (north-south) electric-field component is defined to increase radially and towards higher latitudes. As a check on the numerical solutions, the total energy of the system is continually calculated and compared with the initial energy. Although no damping is included in the problem, the poloidal-mode energy decays with time, as has been shown theoretically. The toroidal mode reaches maximum amplitude in regions of relatively narrow latitudinal extent. The large spatial variation of the magnetic field in these resonance regions must be associated with large field aligned currents. (Author).

Hydromagnetic Waves in the Magnetosphere and the Ionosphere

Hydromagnetic Waves in the Magnetosphere and the Ionosphere PDF Author: Leonid S. Alperovich
Publisher: Springer Science & Business Media
ISBN: 1402066376
Category : Science
Languages : en
Pages : 437

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Book Description
Here is a fascinating text that integrates topics pertaining to all scales of the MHD-waves, emphasizing the linkages between the ULF-waves below the ionosphere on the ground and magnetospheric MHD-waves. It will be most helpful to graduate and post-graduate students, familiar with advanced calculus, who study the science of MHD-waves in the magnetosphere and ionosphere. The book deals with Ultra-Low-Frequency (ULF)-electromagnetic waves observed on the Earth and in Space.

Experimental Study of Hydromagnetic Waves in Plasma

Experimental Study of Hydromagnetic Waves in Plasma PDF Author: Alan Woodruff DeSilva
Publisher:
ISBN:
Category : Magnetohydrodynamic waves
Languages : en
Pages : 130

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Spectrum of Hydromagnetic Waves in the Exosphere

Spectrum of Hydromagnetic Waves in the Exosphere PDF Author: Gordon James MacDonald
Publisher:
ISBN:
Category : Atmosphere, Upper
Languages : en
Pages : 72

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Book Description
A disturbance in the exosphere generates waves in three partially separable modes. These modes are described by considering the vorticity about a line of force, the two-dimensional divergence of velocity in the plane perpendicular to the line of force, and the component of velocity along the line of force. The propagation of vorticity is one-dimensional and there is no geometrical attenuation; energy is lost only through the finite conductivity of the medium. The propagation of the longitudinal velocity component is almost one-dimensional but is heavily damped at high frequencies. In a gravitational field, the medium is no longer uniform and at low frequencies the modes are coupled in a complicated way. For parallel magnetic and gravitational fields, the vorticity mode is still separable and gravity leads to anisotropic dispersion in the other modes.-p.i.

Spectrum of Hydromagnetic Waves in the Exosphere

Spectrum of Hydromagnetic Waves in the Exosphere PDF Author: Gordon J. F. MacDonald
Publisher:
ISBN:
Category : Exosphere
Languages : en
Pages : 72

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Book Description
A disturbance in the exosphere generates waves in three partially separable modes. These modes are described by considering the vorticity about a line of force, the two-dimensional divergence of velocity in the plane perpendicular to the line of force, and the component of velocity along the line of force. The propagation of vorticity is one-dimensional and there is no geometrical attenuation; energy is lost only through the finite conductivity of the medium. The propagation of the longitudinal velocity component is almost one-dimensional but is heavily damped at high frequencies. In a gravitational field, the medium is no longer uniform and at low frequencies the modes are coupled in a complicated way. For parallel magnetic and gravitational fields, the vorticity mode is still separable and gravity leads to anisotropic dispersion in the other modes.

The Transmission of Hydromagnetic Waves Through the Ionosphere

The Transmission of Hydromagnetic Waves Through the Ionosphere PDF Author: Ilan Josip Rothmuller
Publisher:
ISBN:
Category : Ionospheric radio wave propagation
Languages : en
Pages : 334

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Hydromagnetic Wave Propagation in a Constant Dipole Magnetic Field

Hydromagnetic Wave Propagation in a Constant Dipole Magnetic Field PDF Author: John Carstoiu
Publisher:
ISBN:
Category : Magnetic dipoles
Languages : en
Pages : 48

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Propagation of Hydromagnetic Waves in a Stochastic Magnetic Field

Propagation of Hydromagnetic Waves in a Stochastic Magnetic Field PDF Author: George C. Valley
Publisher:
ISBN:
Category : Cosmic magnetic fields
Languages : en
Pages :

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Hydromagnetic Ionizing Waves

Hydromagnetic Ionizing Waves PDF Author: Allen G. Rubin
Publisher:
ISBN:
Category : Electromagnetic waves
Languages : en
Pages : 26

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Book Description
A theory of hydromagnetic ionizing waves has been developed which is valid in the region in which gas pressure is negligible, compared with magnetic pressure. The theory takes into account the energy expended in partial ionization of the gas behind the wave. The usual high conductivity boundary condition behind the wave is not employed. The electric field in front of the wave is taken as a parameter. Results of this theory are compared with available experimental measurements, and show good agreement. (Author).

A Mechanical Analogue for the Study of Hydromagnetic Propagation in the Magnetosphere

A Mechanical Analogue for the Study of Hydromagnetic Propagation in the Magnetosphere PDF Author: Henry R. Radoski
Publisher:
ISBN:
Category : Machinery
Languages : en
Pages : 24

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Book Description
The reduction of the oscillations of the magnetosphere to a simple mechanical analogue, which can be analyzed in detail, is accomplished in three stages: (1) The comparison of the wave equations for a dipole field magnetized plasma to those for a rectangular model of the plasmasphere with a unidirectional field -- the important physical characteristics are shown to be independent of the particular geometry chosen; (2) the comparison of the equations in the above hydromagnetic box with those of a mechanical system consisting of a set of oscillators, representing field lines, coupled by a wave propagating medium -- for the symmetric modes with weak ion-cyclotron coupling, the equations for the hydromagnetic and mechanical systems are essentially identical; (3) the simplification of the mechanical system to an elementary wave-oscillator model representing the coupling between resonant poloidal and toroidal modes -- the nature of the motion of this model is independent of the strength of the coupling. In general, the behavior of coupled and uncoupled modes is essentially different. When any coupling is present, steady state solutions, as normally understood, are not possible. (Author).