Coherent transition radiation (CTR) from relativistic electron beam interaction with an overdense
plasma foil is investigated by making use of two-dimensional particle-in-cell simulations. Well-
defined single electron beam either of uniform profile or having substructures is considered for various
beam-plasma parameters. The main purpose is to mimic the complicated beam-plasma conditions
that is often found, for example, in intense laser plasma interactions. Key properties of the CTR
concerning their temporal, angular and spectral profiles are identified. Several saturation effects due
to the beam energy, size and foil density are found for the CTR energy, and the dependencies vary
for different spectral components such as in the Terahertz (THz) and optical range. The detailed
substructure of the beam also affects greatly the radiation generation, leading to distinctive high
harmonic components. Electrons with kinetic energy from sub MeV to tens of GeV are explored.
For few MeV electron beams, the effects of the foil plasma on the beam dynamics and associated
CTR generation, resembles closely the CTR from hot electrons produced in intense laser-plasma
interactions. These results may find important applications in beam diagnostics either in laser-
plasma based acceleration or conventional accelerators. They may also be employed to design novel
THz radiation sources using tunable electron beams.
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Funding Info:
A*STAR SERC Young Individual Research Grants (YIRG No. A1784c0020).