Relativistic degeneracy effect on propagation of arbitrary amplitude   ion-acoustic solitons in Thomas-Fermi plasmas
  Arbitrary amplitude ion-acoustic solitary waves (IASWs) are studied using Sagdeev-Potential approach in electron-positron-ion plasma with ultra-relativistic or non-relativistic degenerate electrons and positrons and the matching criteria of existence of such solitary waves are numerically investigated. It has been shown that the relativistic degeneracy of electrons and positrons has significant effects on the amplitude and the Mach-number range of IASWs. Also it is remarked that only compressive IASWs can propagate in both non-relativistic and ultra-relativistic degenerate plasmas. 
Abdolrasoul Esfandyari-Kalejahi, Massoud Akbari-Moghanjoughi and Ehsan   Saberian
astro-ph.HE