Magnetosonic hump and dip solitons in a quantum plasma with Bohm potential effect

Abstract

Low frequency nonlinear magnetosonic wave propagation is investigated in magnetized electron ion quantum plasmas. A two fluid quantum magnetohydrodynamic model is employed for a magnetized dense plasma. The quantum effects like Bohm potential (due to wave nature of the particles) and Fermi pressure (due to spin 1/2 particles) for degenerate electrons are taken in the model. The electron inertia is also included in the momentum equation of degenerate electrons, which gives the magnetosonic wave dispersion effects on electron inertial length scale in the linear wave analysis. The Korteweg de Vries (KdV) equation is derived for studying low amplitude magnetosonic solitons in a magnetized quantum plasma by employing a reductive perturbation method. It is found that in the presence of Bohm potential force in quantum plasma model both plasma hump and dip soliton structures of magnetosonic waves are formed. The magnetosonic soliton hump structures moves with super magnetosonic wave speed, while dip magnetosonic wave structures have sub magnetosonic wave speed. The effects of varying plasma parameters such as plasma density and magnetic field intensity on nonlinear structures are discussed and illustrated numerically in the context of astrophysical plasma conditions existing in compact stars.