Propagation of Ion-Acoustic Shock Waves in Magnetized Dense Quantum Plasmas

Abstract

Dense quantum plasmas emerged as an active field of research due to their great pertinence in different areas of practical importance e.g., laser interactions with atomic systems, nanoscale electrochemical systems and in dense astrophysical plasmas such as neutron stars and white dwarfs. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> In dense quantum plasmas, at extremely high number densities the de-Broglie wavelength associated with the charge particle becomes comparable to the interparticle distance. Shocks are generated in the medium due to balance of different kinds of effects such as nonlinear, dispersive and dissipation effects. Shocks have potential applications for acceleration of charged particles in different kinds of plasma environments. The present work focuses on the study of ion-acoustic shock waves in magnetized quantum plasmas with the effects of spin-up and spin-down degenerate electrons. The spin effects are considered as one of the most important properties of quantum plasmas due to great significance of highly magnetized quantum plasmas in the atmospheres of neutron stars. A theoretical investigation has been carried out to study the propagation of shock waves with the density effects of spin-up and spin-down electrons. We have considered quantum plasma in which a uniform magnetic field is applied along positive z-direction. The separated spin evolution quantum hydrodynamics model (QHD) has been used by considering spin-up and spin-down electrons as different species. The Zakharov-Kuznetsov-Burgers (ZKB) equation has been derived by employing reductive perturbation method. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> The effects of density polarization ratio and different plasma parameters on the characteristics of IA shocks have been analyzed. It is seen that spin density polarization ratio significantly affects the characteristics of IA shock waves as we move from strongly spin polarized case to zero spin polarized case. The results obtained in the present investigation may be useful in comprehending various nonlinear excitations in dense astrophysical regions such as, white dwarfs, neutron stars.