QC225 : Investigation of dynamic behavior of electromagnetic waves in electron – positron plasmas
Thesis > Central Library of Shahrood University > Physics > MSc > 2014
Authors:
Kobra taravideh [Author], Mahdi Momeni[Supervisor]
Abstarct: Electron-positron plasmas are a large class of equal-mass and charge (opposite sign) plasmas that exist in the basic structure of the universe, in astrophysical objects such as in pulsar magnetospheres, active galactic nuclei, Decay gamma ray and etc. The electron-positron pairs may be created by collisions between the charged particles that ar accelerated by electromagnetic and/or Gravitational forces. Also in pulsar environment due to High-energy photon radiation and/or in fusion devise such as tokamaks electron-positron pair are produced through collision between Mev electrons and thermal particle. Linear an nonlinear waves in e-p plasmas have different properties from electron-ion plasmas due to the similar dynamics of particles. To investigate the linear effects of plasma, such as the relation of dispersion linear excited waves, we use linear theory. Linear theory is baxsed on the approximation of small amplitude of waves. In this range, we ignored all of second-and higher-order nonlinear terms and their derivatives. According to this theory, physical disorder in the system, behave periodic and independently, and the propagation of waves is shown with linear dispersion relation .To investigate waves we need to obtain the dispersion relation that includes some important physical information like…. The dispersion relations for the longitudinal modes in the absence and presence of a magnetic field are found to be similar to those for the electron-ion plasma. However ,Those for the transverse modes in the presence of a magnetic field are similar but the absence of a magnetic field are found to be quite different from the electron-ion plasma When we me mention nonlinear effects, we mean the behaviors of the plasma that cannot be justify by using the linear theory. These behaviors are basically appear when the amplitude of waves become larger. The solitary waves or Solitons are most important solutions of nonlinear equations that would solve these plasmas.In this study we investigate the effect of some important quantities such as Mukh number, quantum parameter, temperature of electron and positron, magnetic field and etc on electromagnetic and electrostatic solitary wave in quantum and clacssical electron-positron plasma. Notice that the e–p plasma symmetry can break in the presence of
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