Processes of Terahertz Radiation Generation during Emission of a Bunch of Electrons Accelerated by a Short Laser Pulse from a Metal/Plasma Target

A consistent description of terahertz (THz) radiation generation by laser-accelerated electrons from a target irradiated by a short light pulse requires a complete understanding of the contribution of all processes of interaction between emitted relativistic electrons and the target, taking into account the arising self-consistent fields. Despite the fact that the dominant role in this radiation is assumed a priori to be due to transition radiation from electrons leaving the target, in addition to this mechanism, it is necessary to estimate a set of such processes as bremsstrahlung of trapped electrons accelerating and decelerating in the Debye sheath, as well as their transition radiation and synchrotron radiation during the rotation of the double sheath field. This paper, which relies on a physically justified qualitative analysis, does not pretend to be a strict quantitative calculation and uses methodological techniques that aid understanding. Estimates are also presented that allow one to assess the characteristics of the generated THz pulse.