NONLINEAR PROPAGATION OF SMALL-AMPLITUDE MODIFIED ELECTRON-ACOUSTIC SOLITARY WAVES AND DOUBLE-LAYER IN SEMIRELATIVISTIC PLASMAS

Considering an unmagnetized plasma consisting of relativistic drifting electrons and nondrifting thermal ions and by using reductive perturb ation method, a usual Korteweg-de Vries (KdV) equation and a generaliz ed form of KdV equation are derived. It is found that while the former governs the dynamics of a small-amplitude rarefactive modified electr on acoustic (MEA) soliton, the latter governs the dynamics of a weak c ompressive modified electron acoustic double layer. The influences of relativistic effect on the propagation of such a soliton and double la yer are examined. The relevance of this investigation to space plasma is pointed out.