Svystun O. Plasma wakefield excitation by sequences of relativistic electron bunches: numerical simulation

The thesis deals with the theoretical investigation of the basic mechanisms of plasma wakefield excitation by resonant and non-resonant trains of relativistic electron bunches and by single dense relativistic electron bunch. Conditions of attaining the maximum wakefield amplitude excited by a long train of low-density relativistic electron bunches are investigated by numerical simulation for the parameters of the experiment for the resonance case when the bunch repetition frequency coincides with the plasma frequency. The mechanism of resonant excitation of plasma wakefield by a non-resonant train of short electron bunches is proposed and investigated for the first time, taking into account radial dynamics of bunches, for the case when the bunch repetition frequency larger than the plasma frequency. The plasma wakefield excitation by a non-resonant train of relativistic electron bunches for the case of bunch repetition frequency lower plasma frequency is investigated by numerical simulation. The numerical simulation of properties and excitation of wakefield bubble of plasma electrons by short dense bunch of relativistic electrons has been performed. The mechanism of focusing of relativistic electron bunches by plasma wakefield, in which all bunches of a train are focused identically and uniformly, has been proposed and investigated for the first time.