Nonlinear kinetic simulation study of the ion–ion streaming instability in single- and multi-ion species plasmas

The nonlinear evolution of the ion–ion streaming instability (IISI) is studied using numerical techniques novel to this problem that afford direct insight into particle distributions each species. During linear phase instability, we demonstrate quantitative agreement with kinetic theory. Subsequently, electrostatic field generated by IISI causes ring-like velocity ions form are both heated and slowed varying degrees relative their initial flows. Due variation in trapping conditions for ion species differing charge-to-mass ratio, when flows multiple interact, can be starkly different: show a case where lighter completely stopped heavier via alone (i.e., without collisions) and, first time, how introduce flow between initially have same velocities, thereby separating them.