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دسترسی آزاد مقاله
1 - Scattering of quantum hydromagnetic waves in a semiconductor plasma
Zeynab Kiamehr Zohreh KiamehrIn addition to the fact that waves have been proven in different plasma environments, they have also been investigated under different physical regimes. In this research, the propagation of electromagnetic waves in quantum semiconductor plasma in the presence of a unifo چکیده کاملIn addition to the fact that waves have been proven in different plasma environments, they have also been investigated under different physical regimes. In this research, the propagation of electromagnetic waves in quantum semiconductor plasma in the presence of a uniform external magnetic field was investigated using the quantum hydro magnetism model. The researches that have been done so far about these waves have mostly been done in classical or relativistic regimes. Some cases have been studied to study linear waves in quantum plasma, taking into account the quantum Bohm potential without investigating the effect of the spin characteristics of plasma particles. In addition to the simultaneous study of spin and quantum effects of semiconductor plasma components, exchange-correlation relationships have not been found in any research, and the most important novelty of the present work can be considered the addition of these relationships together. The obtained results show that the effects of quantum and external magnetic fields have a significant effect on the scattering of hydromagnetic waves, which causes the appearance of nonlinear terms in the scattering relationship. By increasing the linear part of the electron spin in the sputtering relation, some relations have been modified, including the Alfven velocity. On the other hand, the effect of electron spin leads to the reduction of the effect of other quantum potentials on the scattering of waves. In the end, some special states of classical and quantum systems are also discussed. Considering the limit states, the results of the present work are exactly similar to the results of other researchers, and this can be a self-confirmation of the obtained results. پرونده مقاله -
دسترسی آزاد مقاله
2 - Dispersion characteristics of plasma-filled cylindrical waveguide
Sh. M. Khalil N. M. MousaAbstractAn analytical and numerical study is made on the dispersion properties of a cylindrical waveguide filled with plasma. An electron beam and static external magnetic field are considered as the mechanisms for controlling the field attenuation and possible stabilit چکیده کاملAbstractAn analytical and numerical study is made on the dispersion properties of a cylindrical waveguide filled with plasma. An electron beam and static external magnetic field are considered as the mechanisms for controlling the field attenuation and possible stability of the waveguide. The effects of plasma warmness and inhomogeneity are also considered. Dispersion relations in ω describing different physical situations that govern the mode propagation in the waveguide are obtained. The plasma dielectric tensors and the dispersion relations which describe E and H waves and, hence, the damping rate of these waves are calculated and studied. The necessary conditions for the field stability in the waveguide and amplification coefficients for these waves are also obtained. H-wave modes are always attenuated by collisional effect. The growth of the excited E wave is calculated in the resonance case, and the stability condition for the E wave is obtained. E waves are found to be more stable in warm plasma compared to cold plasma. The results obtained here are of great interest and may be used to analyze how the plasma affects the electromagnetic properties of the cavity of the 1–2 MW 140–170 GHz continuous-wave gyrotron (for W7-X stellarator and ITER), for MW gyrotron development for fusion plasma applications, and for second harmonic generation in a plasma-filled parallel plane waveguide. پرونده مقاله -
دسترسی آزاد مقاله
3 - Theoretical analysis of a thermal plasma-loaded relativistic traveling wave tube having corrugated slow wave structure with solid electron beam
Zahra Javadi Shahrooz SavizAbstractA relativistic traveling wave tube with thermal plasma-filled corrugated waveguide is driven by a finite solid electron beam with the entire system immersed in a strong longitudinal magnetic field that magnetized plasma and electron beam. The dispersion relation چکیده کاملAbstractA relativistic traveling wave tube with thermal plasma-filled corrugated waveguide is driven by a finite solid electron beam with the entire system immersed in a strong longitudinal magnetic field that magnetized plasma and electron beam. The dispersion relation for the relativistic traveling wave tube is obtained by linear fluid theory. The numerical results show that the growth rate decreases by increasing plasma temperature, waveguide radius, plasma density and electron beam energy. As show in this paper the effect of electron beam density and corrugation period is to increase growth rate. پرونده مقاله -
دسترسی آزاد مقاله
4 - Dispersion relation and growth rate in thermal plasma-loaded traveling wave tube with corrugated waveguide hollow electron beam
Samina Dehghanizadeh Shahrooz SavizAbstract A theory of relativistic traveling wave tube with magnetized thermal plasma-filled corrugated waveguide with annular electron beam is given. The dispersion relation is obtained by linear fluid theory. The characteristic of the dispersion relation is obtained by چکیده کاملAbstract A theory of relativistic traveling wave tube with magnetized thermal plasma-filled corrugated waveguide with annular electron beam is given. The dispersion relation is obtained by linear fluid theory. The characteristic of the dispersion relation is obtained by numerical solutions. The effect of plasma density, corrugated period, waveguide radius and plasma thermal effect on the dispersion relation and growth rate are analyzed. Some useful results are given. پرونده مقاله -
دسترسی آزاد مقاله
5 - Influence of the Imperfect Interface on Love-Type Mechanical Wave in a FGPM Layer
S Chaudhary A Singhal S.A SahuIn this study, we consider the propagation of the Love-type wave in piezoelectric gradient covering layer on an elastic half-space having an imperfect interface between them. Dispersion relation has been obtained in the form of determinant for both electrically open and چکیده کاملIn this study, we consider the propagation of the Love-type wave in piezoelectric gradient covering layer on an elastic half-space having an imperfect interface between them. Dispersion relation has been obtained in the form of determinant for both electrically open and short cases. The effects of different material gradient coefficients of functionally graded piezoelectric material (FGPM) and imperfect boundary on the phase velocity of Love-type waves are discussed. Also, the influence of mechanically and electrically imperfect interface on the surface wave phase velocity is obtained and shown graphically. The dispersion curves are plotted and the effects of material properties of both FGPM and orthotropic material are studied. Moreover, dispersion relation of the considered microstructure depends substantially on the material gradient coefficients and width of the guiding plate. Numerical results are highlighted graphically and are validated with existing literature. The present study is the prior attempt to show the interfacial imperfection influence with the considered structure on wave phase velocity. The outcomes are widely applicable and useful for the development and characterization of Love-type mechanical waves in FGPM-layered media, SAW devices and other piezoelectric devices. پرونده مقاله -
دسترسی آزاد مقاله
6 - Torsional Surface Wave Propagation in Anisotropic Layer Sandwiched Between Heterogeneous Half-Space
P.K Vaishnav S Kundu S.M Abo-Dahab A SahaThe present paper studies the possibility of propagation of torsional surface waves in an inhomogeneous anisotropic layer lying between two heterogeneous half-spaces (upper and lower half-space). Both the half-spaces are assumed to be under compressive initial stress. T چکیده کاملThe present paper studies the possibility of propagation of torsional surface waves in an inhomogeneous anisotropic layer lying between two heterogeneous half-spaces (upper and lower half-space). Both the half-spaces are assumed to be under compressive initial stress. The study reveals that under the assumed conditions, a torsional surface wave propagates in the medium. The dispersion relation of torsional surface wave has been obtained in the presence of heterogeneity, initial stress and anisotropic, and it is observed that the inhomogeneity factor due to quadratic and hyperbolic variations in rigidity, density and initial stress of the medium decreases the phase velocity as it increases. The result also shows that the initial stresses have a pronounced influence on the propagation of torsional surface waves. In the absence of anisotropy, Initial stress, inhomogeneity and rigidity of the upper half-space, then the dispersion relation coincide with the classical dispersion relation of Love wave. پرونده مقاله
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