Arbitrary amplitude electrostatic wave propagation in a magnetized dense plasma containing helium ions and degenerate electrons

2016 ◽  
Vol 23 (6) ◽  
pp. 062308 ◽  
Author(s):  
S. Mahmood ◽  
Safeer Sadiq ◽  
Q. Haque ◽  
Munazza Z. Ali
Keyword(s):  
Wave Propagation ◽  
Dense Plasma ◽  
Helium Ions ◽  
Electrostatic Wave ◽  
Arbitrary Amplitude

Plasma models of the topside ionosphere and electrostatic wave propagation

1971 ◽  
Vol 6 (3) ◽  
pp. 567-577 ◽  
Author(s):  
M. T. C. Fang ◽  
M. K. Andrews
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Kinetic Equation ◽  
Ray Tracing ◽  
Good Accuracy ◽  
Topside Ionosphere ◽  
Adiabatic Process ◽  
Kinetic Description ◽  
Electrostatic Wave ◽  
Plasma Dispersion

The circumstances under which certain plasma dispersion equations may be used in electrostatic ray tracing problems connected with studies of ionospheric topside plasma resonances are investigated. Three plasma ‘models’ of increasing complexity are compared with each other. The models are based on the assumption of: (i) an adiabatic process with a scalar pressure, (ii) a fully adiabatic process (Buneman 1961), and (iii) an electrostatic kinetic description. It is found that near fN, and within 10° of the static magnetic field, all three models may be used with good accuracy, and collisionless damping is very small. Near fT, and for propagation nearly across the field, only the second model (ii) gives tolerably accurate results as judged by the kinetic equation. For frequencies within 10 kc s-1 of fT such as are encountered in ray tracing, collisionless damping may be neglected within a cone of ∽ 10° about the perpendicular to the field for fT < 2fH, and within ∽ 20° whenfT ≫ 2fH Model (iii) may be used to examine the dispersion equation near the electron gyroharmonics: this topic is discussed in Andrews & Fang (1971).

Electron Microscopy of Shock Loaded Polycrystalline Beryllium

1974 ◽  
Vol 32 ◽  
pp. 506-507 ◽  
Author(s):  
J. M. Galbraith ◽  
L. E. Murr ◽  
A. L. Stevens
Keyword(s):  
Electron Microscopy ◽  
Wave Propagation ◽  
Structural Change ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Shock Loading ◽  
Slip Systems ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
X Ray

Uniaxial compression tests and hydrostatic tests at pressures up to 27 kbars have been performed to determine operating slip systems in single crystal and polycrystal1ine beryllium. A recent study has been made of wave propagation in single crystal beryllium by shock loading to selectively activate various slip systems, and this has been followed by a study of wave propagation and spallation in textured, polycrystal1ine beryllium. An alteration in the X-ray diffraction pattern has been noted after shock loading, but this alteration has not yet been correlated with any structural change occurring during shock loading of polycrystal1ine beryllium.This study is being conducted in an effort to characterize the effects of shock loading on textured, polycrystal1ine beryllium. Samples were fabricated from a billet of Kawecki-Berylco hot pressed HP-10 beryllium.

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