الفهرس 
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Abstract
Summary and Conclusions
In this work we have studied the excitation and wave propagation in quantum plasma. Our results concentrate on the propagation of different linear waves under the quantum effects (Bohm potential, spin effect) in dense quantum plasmas.
In chapter (1), an introduction to the various occurrences of quantum plasmas in nature and in the laboratory comparing to the classical plasmas are given. Also, the parameters and characteristics of quantum plasmas and its recent developments have been investigated. The waves in plasma are illustrated, and the surface wave is discussed in detail. The quantum plasma is described in this chapter and the conditions to treat plasma as a quantum instead of classical system are given. Also the quantum effects are deduced. The semiconductor plasmas is explained as one of the high topics in research in plasma physics nowadays. Finally, the previous work are included and our plan.
In chapter (2), the various models which are widely used as a tool to describe a quantum plasmas are discussed. The classical models are illustrated in the first section of the chapter and then the quantum models are discussed in more detail. The validity of the various models is hinted.
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In the first part of chapter (3), we have considered the influence of the intrinsic spin of electrons on the excitation of transverse electromagnetic surface waves in a magnetized plasma. By using a fluid formalism, we enabled to include quantum corrections which appeared due to the Bohm potential and the magnetization energy of electrons, as the last is due to the electrons spin. The effects of the quantum corrections appeared in the dispersion relation belongs to the propagation of the surface waves. Besides, the phase velocity and the group velocity are founded to increase according to the quantum effects. By studying the nonrelativistic motion of the electrons, we found that the spin effects became remarkable even if the external magnetic field is comparatively low.
In the second part of chapter (3), the excitation of electrostatic surface waves on a semi-bounded quantum plasma-vacuum interface parallel to an applied magnetic field with electron-hole degeneracy is investigated. The wave equations of the electrostatic potential and both of the perturbed electron and hole plasma densities have been solved analytically. By using quantum hydrodynamic (QHD) model and the Poisson’s equation with appropriate boundary conditions, the general dispersion relation of these surface modes has been obtained. It is also solved and studied numerically for different cases of plasmas (magnetized or unmagnetized, classical or quantum). We have found that the density ratio of the hole-electron plasma play an essential role on the dispersion of the modes along the wavelength beside the previously mentioned quantum effects and magnetic field.
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Conclusions
The contribution of the quantum effects led to the appearance of a correction terms in the dispersion relation, which in turn gives an excess to other new modes. The quantum effects (Fermi pressure, Bohm Potential, and spin effect) play an essential role in the propagation of the surface waves in Quantum plasma under the influence of an external magnetic field. The phase and the group velocities are increased due to the quantum effects. Also, it is noticed that the increase of the magnetic field leads to increase the frequency of the excited modes. Besides, when the spin effect considered, the result is similar to the influence of increasing the magnetic field. Also, the quantum effects increase the phase and group velocities in an electrostatic electron-hole plasma. Besides, the hole-electron density ratio plays an essential role in modifying the phase velocity which in turn modify the energy of the surface wave.
These results can be used to improve the efficiency of the semiconductor plasmas in computer chips. We can increase the velocity of the surface waves that transfer data in them by increasing the hole-electron density ratio, which in turn increases the velocity of data transfer.