Soliton Characteristics at the Critical Density of Negative Ions in Ion-beam Plasmas

Abstract

By using the reductive perturbation technique, ion-acoustic waves are studied in a generalised multicomponent plasma. The multiple ions modify drastically the characteristics of the solitary waves. In particular, the negative ions have a critical density at which the nonlinearity of the Korteweg-deVries (K-dV) equation vanishes and the ion-acoustic solitary wave is seen to be described by a modified K-dV (mK-dV) equation. Using higher order nonlinearities, the non-uniform transition of the K-dV equation to the mK-dV equation along with the conservation of the Sagdeev potential is described. Theoretical observations on the existence of the solitary waves, as expected, could be of interest in laboratory plasmas