Nucleus-acoustic solitary waves and double layers in a magnetized degenerate quantum plasma

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