Super-filament formation of a relativistic Gaussian electron beam in a dense collisional plasma

Energy flux transport of a finite high current relativistic electron beam with the Gaussian profile in both the transverse and axial directions in a dense collisional background plasma is studied by means of three-dimensional particle-in-cell simulations. Simulation results reveal the development of a needle-like super-filament formation in both homogeneous as well as inhomogeneous collisional background plasmas. However, in the case of an inhomogeneous background plasma, the beam suffers severe filamentation due to the lower plasma density encountered in the early stage, and only the head of the super-filament survives and travels further inside the plasma. This may not be desirable for the fast ignition fusion scheme.