Dissipation of weakly nonlinear wakefields due to ion motion

In an initially uniform plasma, the lifetime of a weakly nonlinear plasma wave excited by a short driver is limited by the ion dynamics. The wakefield contains a slowly varying radial component, which results in a perturbation of the ion density profile and consequent destruction of the plasma wave. We suggest a novel method of characterizing the wave lifetime in numerical simulations quantitatively and study how the lifetime scales with the ion mass. We also discuss the implications of the limited lifetime on a recently proposed method of generating high-power terahertz radiation with counterpropagating wakefields driven by colliding laser pulses.