Localized electrostatic excitations and higher-order nonlinear effects in warm pair plasmas

Summary form only given as follows. The propagation of small amplitude nonlinear electrostatic waves propagating parallel to the external magnetic field in pair plasma (consisting of two species of equal mass and opposite charge) is investigated. The basic set of fluid equations is reduced to a Korteweg-de Vries (KdV) equation coupled to a linear inhomogeneous equation for the first and second-order perturbed potential corrections, respectively. The system is solved via a renormalization method. It is shown that higher-order nonlinearity modifies (deforms) the soliton amplitude (the soliton shape). It is found that KdV solitons do not exist when the temperature of negative ions T_- equals that of positive ions T₊ , i.e. for sigma = T₊/T_- = 1. On the other hand, it is observed that the absolute value of the amplitude of the lower-order solitary pulses increases as sigma increases for both sigma < 1 (positive potential pulses) and sigma > 1 (negative potential pulses). These results are in agreement with and extend previous results on pair plasmas.