Decay instability of electron acoustic waves

Eulerian and particle in cell (PIC) simulations are used to investigate the decay instability of electron acoustic waves (EAWs). An EAW is a nonlinear wave with a carefully tailored trapped particle population, that can be excited by a relatively low driver amplitude, if the driver is applied resonantly over many trapping periods. The excited EAW rings at nearly constant amplitude long after the driver is turned off, provided the EAW has the longest wavelength that fits in the plasma. Otherwise, the EAW decays to a longer wavelength EAW, through a vortex-like trapped particle population merging.