Passage of an ion-acoustic solitary wave through the boundary between an electron-ion plasma and a negative ion plasma

Abstract

The passage of an ion-acoustic solitary wave through the boundary between an electron-ion plasma and a negative ion plasma is considered. After the ion-acoustic solitary wave enters the region of another plasma, a disturbance arises, from which an ion-acoustic solitary wave and a chain of oscillations form over time. The amplitude of the ion-acoustic solitary wave after passage through the boundary changes in such a way that its value in the electron-ion plasma is greater than its value in the negative ion plasmas. An exception is the case of a compressive ion-acoustic solitary wave propagating through the negative ion plasma and having an amplitude exceeding the critical amplitude in the electron-ion plasma. Such an ion-acoustic solitary wave, when entering an electron-ion plasma, releases an excess of energy to accelerate positive ions and thereby reduces its amplitude below the critical value. The dependence of the amplitude of an ion-acoustic solitary wave established after the boundary crossing on its initial amplitude is determined. The passage of an ion-acoustic solitary wave through a layer of negative ion plasma surrounded by electron-ion plasmas is considered. It is shown that the passage of a rarefactive ion-acoustic solitary wave from the negative ion plasma into the electron-ion plasma causes disturbance, in which accelerated and trapped negative ions can be observed.