WAVE PROPAGATION IN A CYLINDRICAL WAVE GUIDE CONTAINING INHOMOGENEOUS PLASMA INVOLVING A TURNING POINT

1963 ◽  
Vol 41 (1) ◽  
pp. 113-131 ◽  
Author(s):  
S. N. Samaddar
Keyword(s):  
Electric Fields ◽  
Electromagnetic Waves ◽  
Turning Point ◽  
Boundary Effect ◽  
Inhomogeneous Plasma ◽  
Simple Zero ◽  
Wave Guide ◽  
Wave Number ◽  
Axially Symmetric ◽  
Radial Wave

Propagation of axially symmetric E-type and H-type modes of electromagnetic waves in a radially inhomogeneous plasma inside a wave guide is considered. For E-type modes conditions for the propagation of slow surface waves along the plasma–dielectric interface have been obtained. Approximate expressions for fields for wavelengths much smaller than the ratio of the gradient of the permittivity to the permittivity of the plasma are also given.It is also shown that if the dielectric constant ε(r) of the plasma vanishes along a particular surface r = r0, the electromagnetic fields for E-type modes behave singularly along this surface. In particular, if ε(r) has a simple zero at r0 ≠ 0, the radial and the longitudinal electric fields become singular as 1/ε(r0) and log ε(r0) respectively at r0. On the other hand, if ε(r) has a multiple zero at r0, the singularities of the above-mentioned fields will be as strong as a multiple pole at r0.Turning-point phenomena are also observed when the radial wave number [Formula: see text] vanishes along a surface. It is shown that the fields are oscillatory in the region [Formula: see text] and evanescent in the region [Formula: see text] for both E-type and H-type modes. The treatment of the singular behavior of the fields at ε(r) = 0, and of the turning-point phenomena at [Formula: see text], does not consider any boundary effect; therefore the results obtained here will be valid also for an inhomogeneous plasma column in free space.

scholarly journals Low-to-High Confinement Transition Mediated by Turbulence Radial Wave Number Spectral Shift in a Fusion Plasma

2016 ◽  
Vol 116 (9) ◽  
Author(s):  
G. S. Xu ◽  
B. N. Wan ◽  
H. Q. Wang ◽  
H. Y. Guo ◽  
V. Naulin ◽  
...  
Keyword(s):  
Spectral Shift ◽  
Wave Number ◽  
Fusion Plasma ◽  
Radial Wave

MUTUAL NONLINEAR INTERACTION OF A NUMBER OF ELECTROMAGNETIC WAVES IN A PLASMA

1963 ◽  
Vol 41 (10) ◽  
pp. 1702-1711 ◽  
Author(s):  
Mahendra Singh Sodha ◽  
Carl J. Palumbo
Keyword(s):  
Wave Equation ◽  
Electric Fields ◽  
Current Density ◽  
Nonlinear Interaction ◽  
Electromagnetic Waves ◽  
Physical Significance ◽  
Mutual Interaction ◽  
Modulated Waves ◽  
Boltzmann's Equation ◽  
Uniform Plasma

In this communication the authors have obtained an expression for current density in a slightly ionized uniform plasma in the presence of a number of electric fields of different frequencies by solving the appropriate Boltzmann's equation. This expression along with the wave equation has been used to investigate the nonlinear mutual interaction of a number of electromagnetic waves, propagating in a plasma. Limitations of the present analysis have also been indicated and the physical significance of the results has been discussed. The technique has also been applied to investigate the mutual interaction of amplitude-modulated waves, and the results express a generalization of Luxembourg effect to a number of strong modulated waves.

scholarly journals Axially Symmetric Vibrations of Composite Poroelastic Spherical Shell

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Rajitha Gurijala ◽  
Malla Reddy Perati
Keyword(s):  
Wave Propagation ◽  
Phase Velocity ◽  
Spherical Shell ◽  
Wave Number ◽  
Biot’S Theory ◽  
Impervious Surfaces ◽  
Axially Symmetric ◽  
Spherical Shells ◽  
Biot's Theory

This paper deals with axially symmetric vibrations of composite poroelastic spherical shell consisting of two spherical shells (inner one and outer one), each of which retains its own distinctive properties. The frequency equations for pervious and impervious surfaces are obtained within the framework of Biot’s theory of wave propagation in poroelastic solids. Nondimensional frequency against the ratio of outer and inner radii is computed for two types of sandstone spherical shells and the results are presented graphically. From the graphs, nondimensional frequency values are periodic in nature, but in the case of ring modes, frequency values increase with the increase of the ratio. The nondimensional phase velocity as a function of wave number is also computed for two types of sandstone spherical shells and for the spherical bone implanted with titanium. In the case of sandstone shells, the trend is periodic and distinct from the case of bone. In the case of bone, when the wave number lies between 2 and 3, the phase velocity values are periodic, and when the wave number lies between 0.1 and 1, the phase velocity values decrease.

Electric fields and electromagnetic waves

1981 ◽  
Vol 19 (1) ◽  
pp. 50-51 ◽  
Author(s):  
George A. Dulk ◽  
Robert Stoller
Keyword(s):  
Electric Fields ◽  
Electromagnetic Waves

DEFORMED SHELL CLOSURES FOR LIGHT ATOMIC CLUSTERS

2008 ◽  
Vol 22 (28) ◽  
pp. 4917-4935 ◽  
Author(s):  
R. A. GHERGHESCU ◽  
D. N. POENARU ◽  
A. SOLOVYOV ◽  
W. GREINER
Keyword(s):  
Input Data ◽  
Energy Levels ◽  
Radial Wave Function ◽  
Atomic Clusters ◽  
Shell Correction ◽  
Axially Symmetric ◽  
Cylindrical Coordinates ◽  
Radial Wave ◽  
Shell Effects ◽  
Shell Closures

The spheroidal shell model of the Nilsson type is used to describe the deformed states of atomic clusters. The Hamiltonian is analytically solved in cylindrical coordinates, where l2 term is treated as deformation-dependent. The usual asymptotic eigenfunctions are obtained for axially symmetric potentials without approximation, and the radial wave function usually employed for further computation is no longer needed. The energy levels obtained in such a way are used as input data for shell correction calculations. Minima due to shell effects are obtained as a function of the number of atoms in the atomic cluster as well as the δ-deformation-dependent. Calculations are performed for N up to 200, and spheroidally (oblate and prolate) deformed shell closures are predicted.

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