Ion-acoustic solitary, breathers, and freak waves inadegenerate quantum plasma

Abstract

In this investigation, the characteristics of ion acoustic (IA) solitary, breathers, and freak waves have been examined by using spin evolution quantum hydrodynamic model in a degenerate quantum plasma consisting of inertial non-degenerate ions and degenerate electrons with spin-up and spin-down states. The Korteweg–de Vries (KdV) equation is derived by employing reductive perturbation technique and its solution is determined to see the existence of IA solitary waves. Only positive potential solitary structures are formed. Further, using appropriate transformation, the KdV equation is transformed into nonlinear Schrödinger equation (NLSE) and its different order solutions are used to study the characteristics of breathers such as the Akhmediev breather, the Kuznetsov–Ma breather and freak waves. Further, the formation of super order of freak waves has also been explored. The influence of different plasma parameters including density polarization ratio has been investigated on the characteristics of IA solitary waves and different types of breathers. It is observed that the density polarization ratio has a strong influence on the characteristics of different types of nonlinear structures. The present investigation may be of great importance to provide physical insight to understand nonlinear dynamical processes in dense astrophysical regions such as white dwarfs and neutron stars.