Ion-Acoustic Solitary Waves and Double Layers in a Magnetized Degenerate Quantum Plasma

The properties of ion-acoustic (IA) solitary waves (SWs) and double layers (DLs) in a four-component magnetized degenerate quantum plasma system (containing nondegenerate inertial light ion, both nonrelativistically and ultrarelativistically degenerate electrons and positrons, and immobile heavy ion) are theoretically investigated by the reductive perturbation method. The Korteweg-de Vries (K-dV), the modified K-dV, and the Gardner equations are derived to examine the basic features (viz. amplitude, speed, and width) of IA SWs and DLs. It is found that the effects of the ultrarelativistically degenerate electrons and positrons, stationary heavy ion, external magnetic field (obliqueness), and so on, significantly modify the basic features of the IA SWs and DLs. The basic features and the underlying physics of IA SWs and DLs, which are relevant to some astrophysical compact objects including white dwarfs and neutron stars, are pinpointed.