Face-to-face Interactions of Breathers in Electron-Ion Plasma with the Critical Composition of an Electron Beam

In the present work, the collisions of weakly nonlinear wave structures in an unmagnetized plasma comprising inertial ions, Maxwellian distributed electrons, and electron beams are analyzed based on experimental data. The study focuses on face-to-face collisions involving breather–breather interaction. To carry out this analysis, the extended Poincaré–Lighthill–Kuo (PLK) reductive perturbation method is employed, leading to the derivation of two coupled Korteweg–de Vries (KdV) equations. At a critical value of the number density ratio, two coupled modified Korteweg–de Vries (mKdV) equations are used to study breather–breather interaction of the ion-acoustic wave. The effects of the electron beam-to-ion density ratio ($\rho_b$) at equilibrium—on the colliding breather profiles are examined. The plasma parameter values used in the analysis are taken from the interplanetary space environment.