The structure of ion-acoustic waves in a low-frequency three-component electron–ion space plasma with two-electron populations

Abstract

Low-frequency ion-acoustic waves are analysed on the ion time-scale, in a three-component electron–ion space plasma. The solitary waves propagate in the positive x direction relative to an ambient magnetic field $$\vec {B}_0$$ which forms static background for a configuration consisting of cool fluid ions and both warm and hot Boltzmann-distributed electrons with temperatures $$T_{ic},$$ $$T_{ew}$$ and $$T_{eh},$$ respectively. We derive linear dispersion relation for the waves by introducing first-order density, pressure and velocity perturbations into the ion fluid equations. Additionally, the variation in the nonlinear structure of the waves are investigated by carrying out a full parametric analysis utilising our numerical code. Our results reveal that ion-acoustic waves exhibit well-defined nonlinear spikes at speeds of $$M\ge 2.25$$ and an electric field amplitude of $$E_0=0.85.$$ It is also shown that low wave speeds $$(M\le 2),$$ higher densities of the hot electrons, antiparallel drifting of the cool fluid ions, and increased ion temperatures all lead to significant dispersive effects. The ion-acoustic plasma waves featured in this paper have forms that are consistent with those classified as the type-A and type-B broadband electrostatic noise (BEN) observed in the data obtained from earlier satellite missions.