Comment on the article 'Solitary waves and double layers in an ultra-relativistic degenerate dusty electron-positron-ion plasma' [Phys. Plasmas extbf{19}, 033705 (2012)]

摘要

More recently, N. Roy et al. [Phys. Plasmas \textbf{19}, 033705 (2012)] haveinvestigated the occurrence of nonlinear solitary and double-layers in anultrarelativistic dusty electron-positron-ion degenerate plasma using a Sagdeevpotential method. They have considered a full parametric examination onMach-number criteria for existence of such nonlinear excitations using thespecific degeneracy limits of Chandrasekhar equation of state (EoS) forFermi-Dirac plasmas. In this comment we point-out a misleading extension ofpolytropic EoS to study the Fermi-Dirac relativistically degenerate plasmas.