Ion-acoustic solitary waves in fully relativistic electron-ion plasmas

The possibility of ion-acoustic solitary waves in a fully relativistic plasma comprised of electrons and ions is investigated by the pseudopotential method. Applying the gas-dynamic approach developed by McKenzie [Phys. Plasmas 9, 800 (2002)] to the energy conservation laws, it is shown that, as in nonrelativistic plasmas, only compressive ion-acoustic solitary waves are possible in two-component relativistic plasmas in the case where the ions are supersonic and electrons are subsonic. It is also shown that, by introducing the relativistic ion-acoustic velocity, various existence conditions for the solitary waves in relativistic two-fluid plasmas can be cast into forms that are identical to the nonrelativistic counterparts found by the gas-dynamic approach. It can be suggested that the method presented in this study can be extended for the investigation of other kinds of electrostatic solitary waves in relativistic multicomponent plasmas