Ion Velocity and Energy Distribution Functions Perturbed by the Ion-Acoustic Solitons: Analytical Calculation for Arbitrary Amplitudes

Distribution functions of background ions perturbed by the ion-acoustic solitons are calculated using the Sagdeev pseudopotential approach for the case of cold ions. Velocity and kinetic-energy distribution functions are analyzed. Explicit expressions valid for the solitons of arbitrary amplitude are obtained. It is demonstrated that the solitons form a strongly nonequilibrium plasma in their vicinity. The results are compared with previous analytical calculations and results of simulations.