Nonlinear Acoustic Modes Inside White Dwarfs

This study delves into the complex behavior of nucleus-acoustic waves (NAWs) within gyro-gravitating degenerate quantum plasmas (DQPs) in spherical geometry. It comprises of classical non-degenerate lighter nuclear species (LNS), heavy nuclear species (HNS); and quantum degenerate electronic species (DES). It considers the Coriolis rotation, viscoelasticity, etc. The model practically mimics the white dwarf interiors. A reductive perturbation method (RPM) over it yields a coupled extended-paired Korteweg-de Vries (ep-KdV) equation governing the electro-gravitational potential fluctuations. The ep-KdV system numerically reveals that the fluctuations evolve as overshot solitary pulse trains, but with a gradual increase in the fluctuation amplitude, boosted at the cost of intrinsic equilibrium energy. The amplitude growths for both types of fluctuations are fully examined in both the non-relativistic (NR, core) and ultra-relativistic (UR, mantle) domains. It could be extensively useful in nonlinear asteroseismology featuring compact astrophysical objects of the white dwarf family.