Ion Acoustic Solitary Waves in Degenerate Electron-Ion Plasmas

Employing the reductive perturbation method, a rigorous study of ion acoustic solitary waves (IASWs) in dense electron-ion plasmas is carried out leading to two evolution equations. Both the nonrelativistic and ultrarelativistic degenerate electron cases are considered. It is found that the relativistic parameter R
₀
affects the IASW phase velocity. Stationary solutions of the derived evolution equations are estimated. The higher order contributions of the nonlinear and dispersion terms are calculated. It has been shown that it is more important to be included in the case of nonrelativistic electrons. These findings are devoted to explaining the observed solitary waves propagating in the outer periphery of compact dense stars, which mostly consists of hydrogen and helium ions with degenerate electrons.