Browsing by Author "Ali, M. Hossain"

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    Interaction Phenomena of Nonlinear Waves in Unmagnetized Plasmas
    (University of Rajshahi, Rajshahi, 2019) Alam, Mohammad Shah; Talukder, Mamunur Rashid; Ali, M. Hossain
    This dissertation is concerned with the study of interaction phenomena of nonlinear waves in unmagnetized plasmas. The plasma system considered is fully ionized, collisionless and homogeneous and/or inhomogeneous that contains multi-component plasma species under different situations. To investigate the physical issues of the interaction phenomena of nonlinear waves the nonlinear evolution equations are derived. The extended Poincaré-Lighthill-kue (ePLK) method is used to derive the nonlinear evolution equations. The interaction phenomena pertaining to plasma parameters on the production of ion-acoustic solitary waves, ion-acoustic shock waves and rogue waves and their consequences on phase shifts and amplitudes are investigated in different plasma situation. The interaction processes among the waves (such as ion-acoustic solitary waves, ion-acoustic shock waves) for single and multi-soliton plasmas are also studied considering the analytical solutions to the nonlinear evolution equations under some assumptions to discuss the characteristic of the waves in the plasmas that are observed in astrophysical, space and laboratory plasmas. In chapter one, some important physical terms that are relevant to the plasma phenomena are briefly discussed. Chapter two discusses the interaction phenomena of ion-acoustic multi-solition and the production of rogue waves in an unmagnetized plasmas composing non-relativistic as well as relativistic degenerate electrons and positrons, and inertial non-relativistic helium ions. The interaction phenomena are investigated by deriving two-sided Korteweg-de Vries (KdV) equations with their corresponding phase shifts employing extended Poicaré-Lighthill-Kuo (ePLK) method and to study the properties of rogue waves the nonlinear Schrödinger equation (NLSE) is obtained from the modified KdV (mKdV) equation.-------
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    Spinning Particles in Curved Spacetime of General Relativity
    (University of Rajshahi, 2001) Ali, M. Hossain; Ahmed, Mainuddin
    In Introduction we give a brief account of our work of studying spinning particles in curved spacetime of General Relativity. In Chapter I we discuss the relevant equations for the motion of spinning particles in curved spacetime. We present the generalized Killing equations for spinning space and describe the constants of motion. In Chapter II we derive the constants and the equations of motion for spinning particles moving in the Schwarzschild spacetime. We discuss various types of orbits and describe exact solutions in a plane. In Chapter III we extend the work of Chapter II in the Reissner-Nordstrom spacetime, which is the Schwarzschild spacetime generalized with a charged parameter and then further extend this work in the Reissner-Nordstrom spacetime generalized with a NUT (or magnetic mass) parameter. In the Reissner-Nordstrom spacetime we investigate the motion of spinning particles on a plane for bound state orbits, while in the NUT-Reissner-Nordstrom spacetime we analyze the motion on a cone and on a plane……….