Analysis of Dispersion and Damping of Ion Waves in Plasma

1998 ◽  
Vol 53 (9) ◽  
pp. 747-750
Author(s):  
A.-A. Turky
Keyword(s):  
Phase Velocity ◽  
Plasma Frequency ◽  
Experimental Results ◽  
Landau Damping ◽  
Frequency Range ◽  
Ion Plasma ◽  
Damping Rate ◽  
Theoretical Predictions ◽  
Ion Waves ◽  
Analysis Of Dispersion

Abstract Experimental results are presented on the dispersion and damping of ion waves having a frequency range extending up to the ion plasma frequency. It was found that the Landau damping rate increases exponentially when the frequency of the ion wave approaches the ion plasma frequency ; while its phase velocity decreases slightly. The experimental results agree reasonably with previous theoretical predictions. The study indicates significant changes in Landau damping even with small variations in the wave velocity.

Propagation of longitudial ion waves near and above ion plasma frequency in a plasma

1968 ◽  
Vol 26 (7) ◽  
pp. 333-334 ◽  
Author(s):  
N. Sato ◽  
H. Ikezi ◽  
Y. Yamashita ◽  
N. Takahashi ◽  
T. Obiki
Keyword(s):  
Plasma Frequency ◽  
Ion Plasma ◽  
Ion Waves

Nonlinear dispersion of surface waves in a plasma column

1984 ◽  
Vol 31 (2) ◽  
pp. 177-191 ◽  
Author(s):  
D. Grozev ◽  
A. Shivarova
Keyword(s):  
Phase Velocity ◽  
Surface Waves ◽  
Plasma Column ◽  
Fundamental Wave ◽  
Third Order ◽  
Ion Plasma ◽  
Wave Phase Velocity ◽  
Collisional Damping ◽  
Damping Rate ◽  
Symmetric Surface

The effect of the nonlinear changes of the dispersion characteristics of highfrequency azimuthally symmetric surface waves in a plasma column is investigated theoretically. Both (ω + ω) – ω and (ω – ω) + ω nonlinear interactions of the third order (in relation to the fundamental wave amplitude) are considered here. These two types of interactions influence the wave phase velocity and the collisional damping rate in opposite ways. When ω2Pi/v2 < 1, the contribution of the (ω – ω) – ω interaction is negligible and the (ω + ω) – ω interaction results in an increase of the phase velocity and a decrease of the time damping rate. When ω2pi/v2 > 1, both interactions are involved; the (ω – ω) + ω interaction associated with the ponderomotive force becomes more important, decreasing the phase velocity and increasing the time damping rate (ωpi and v are ion plasma and electron-neutral collision frequencies, respectively).

scholarly journals Gravitational Landau damping for massive scalar modes

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Fabio Moretti ◽  
Flavio Bombacigno ◽  
Giovanni Montani
Keyword(s):  
Phase Velocity ◽  
Vlasov Equation ◽  
Landau Damping ◽  
Maxwell Distribution ◽  
Massive Scalar ◽  
Numerical Techniques ◽  
Damping Rate ◽  
Scalar Waves

AbstractWe establish the possibility of Landau damping for gravitational scalar waves which propagate in a non-collisional gas of particles. In particular, under the hypothesis of homogeneity and isotropy, we describe the medium at the equilibrium with a Jüttner–Maxwell distribution, and we analytically determine the damping rate from the Vlasov equation. We find that damping occurs only if the phase velocity of the wave is subluminal throughout the propagation within the medium. Finally, we investigate relativistic media in cosmological settings by adopting numerical techniques.

scholarly journals Broadband bifunctional Luneburg–Fisheye lens based on anisotropic metasurface

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jiaqing Chen ◽  
Yongjiu Zhao ◽  
Lei Xing ◽  
Zheng He ◽  
Luyang Sun
Keyword(s):  
High Efficiency ◽  
Broad Band ◽  
Dipole Antenna ◽  
Wide Frequency Range ◽  
Experimental Results ◽  
Frequency Range ◽  
Fisheye Lens ◽  
Low Profile ◽  
Theoretical Predictions ◽  
Fisheye Lenses

AbstractLuneburg lenses and Maxwell fisheye lenses possess distinct properties of focusing, well beyond conventional lenses made of uniform materials. In this paper, a planar broadband bifunctional Luneburg-fisheye lens synthesized by gradient anisotropic metasurface is proposed. The proposed anisotropic metasurface is formed by non-resonant anisotropic cells, so that it can independently realize the equivalent gradient refractive indexes of Luneburg lens and Maxwell fisheye lens along orthogonal directions in a broad band, respectively. To verify the performance of the bifunctional lens, a prototype associated with a feeding log-periodic dipole antenna has been fabricated. Experimental results show that the proposed lens functions well over a wide frequency range with high efficiency and low profile, which coincides well with theoretical predictions and simulated results. It is expected that the proposed design will facilitate the applications of multifunctional metadevices in microwave and optical ranges.

scholarly journals Quantitative Experimental and Theoretical Investigations on the Interaction of Shock Waves with Magnetic Fields

1969 ◽  
Vol 24 (10) ◽  
pp. 1449-1457
Author(s):  
H. Klingenberg ◽  
F. Sardei ◽  
W. Zimmermann
Keyword(s):  
Magnetic Fields ◽  
Shock Waves ◽  
Physical Model ◽  
Spectroscopic Method ◽  
Experimental Results ◽  
Dimensional Theory ◽  
One Dimensional ◽  
Theoretical Investigations ◽  
Theoretical Predictions ◽  
Interaction Of Shock Waves

Abstract In continuation of the work on interaction between shock waves and magnetic fields 1,2 the experiments reported here measured the atomic and electron densities in the interaction region by means of an interferometric and a spectroscopic method. The transient atomic density was also calculated using a one-dimensional theory based on the work of Johnson3 , but modified to give an improved physical model. The experimental results were compared with the theoretical predictions.

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