Modulation of ion beams by relativistic electron beam-plasma instability*

Two-dimensional (2D) electromagnetic particle-in-cell (PIC) simulations are performed to investigate the transport of relativistic electron beams co-moved with a proton beam in collisionless plasmas. For the beam with the radius much larger than plasma skin depth, the current filamentation instability excited by the relativistic electron beam can be clearly observed and the transverse magnetic fields in the plasma increase significantly. The proton beam is modulated strongly by the electromagnetic fields in plasmas and a netlike structure in the beam profile is formed with a high density contrast, which can be provided as an effective tool to diagnose the instability. The dynamic effects of plasma ions are shown to be important and play a significant role on the dynamic evolution of the proton beam.