Study of Solitons and Vortex Formation in Dense Quantum Plasmas

Abstract

By employing quantum hydrodynamic model, the nonlinear dynamics of ionacoustic waves in a collisional, nonuniform quantum magnetoplasma is investigated in the presence of ion sheared flow. It is shown that the parallel ion shear flow can drive the quantum ion-acoustic wave unstable, in the linear case. Whereas, in the nonlinear case, possible stationary solutions of the nonlinear set of equations is obtained in the form of various types of vortices. It is shown that the inclusion of the quantum statistical and Bohm potential terms significantly modify the scale-lengths of nonlinear structures. It is pointed out that this investigation can be applicable to dense astrophysical and laboratory plasmas where the quantum effects would play significant role. It is shown that large amplitude ion-acoustic waves in a nonuniform electronpositron-ion plasma can give rise to monopolar, dipolar and vortex street type structures in dense quantum plasma with sheared ion flows. Linear and nonlinear properties of quantum dust-acoustic waves are also studied in the presence parallel dust sheared flow for inhomogeneous dissipative dustcontaminated magnetoplasma. It is shown that in the linear case, the shear dust flow parallel to the external magnetic field can drive the quantum dust-acoustic wave unstable provided it has a negative slope. On the other hand, in the nonlinear case, stationary solutions of the nonlinear mode coupling equations which govern the dynamics of quantum dust-acoustic waves can be represented in the form of various types of nonlinear vortex structures, Again, in this case, we found that the inclusion of quantum statistical and Bohm potential terms significantly modify the scale-lengths of the vortex structures. We have also revisited the coupled Shukla-Varma and convective cell mode for classical and quantum dusty magnetoplasma. We found that the inclusion of electron thermal effects modify the classical coupled Shukla-Varma and convective cell mode. We also discuss how the quantum statistical and Bohm potential terms can be incorporated in the said mode. The dust-ion-acoustic solitons and shock waves are also investigated in a nonuniform quantum dusty plasma case by employing the quantum hydrodynamic model. By using the small amplitude perturbation expansion method, KdV and KdVB types of equations are derived. The dissipation is introduced by taking into account the kinematic viscosity among the plasma constituents. Our numerical results show that the strength of the quantum dust-ion-acoustic shock wave is maximum for spherical, intermediate for cylindrical and minimum for the planar geometry case. The effects of quantum Bohm potential, dust concentration and kinematic viscosity on the quantum dust-ion-acoustic shock structure are also investigated. Finally, the temporal evolution of dust-ion-acoustic KdV solitons and Burger shocks are also investigated by putting the dissipative and dispersive coefficients equal to zero. The effects of quantum Bohm potential on the stability of dust-ion-acoustic shock is also investigated. It is pointed out that the relevance of present investigation might be in microelectronic devices as well as in dense astrophysical plasmas.