Search Results (4 total)

One possible way to demonstrate both the efficiency and beam quality in a plasma wakefield accelerator is to prepare matched drive and accelerated beams by removing a central slice from a single high-quality electron bunch (parent beam). For parameters of the parent beam given, the question arises how to maximize the number and energy of accelerated particles and minimize their energy spread and emittance. This question is addressed by numerical simulations. The optimum shape of the beams, required plasma length, achievable energy gain, and energy spread are found as functions of the plasma density and parent beam characteristics. The required control accuracy of adjustable beam and plasma parameters is determined.

A wide region of beam parameters is numerically scanned and the dependence of wakefield properties on the beam length and current is clarified for the blowout regime of beam-plasma interaction. The main regimes of the plasma response are found, which qualitatively differ in the plasma behavior. To characterize the efficiency of the energy exchange between the beam and the plasma, the energy flux through the comoving window is introduced. Scalings of the energy flux for the linear plasma response and the main blowout regimes are studied. The most efficient energy transfer occurs in the so-called “strong beam” regime of interaction. For this regime, analytical approximations for various aspects of the plasma response are obtained.

For simulations of plasma wakefield acceleration (PWFA) and similar problems, we developed two-dimensional fully electromagnetic fully relativistic hybrid code LCODE. The code is very fast due to explicit use of several simplifying assumptions (quasistatic approximation, ultrarelativistic beam, and the symmetry). With LCODE, we make high-resolution simulations of the blowout regime of PWFA and study the temperature effect on the amplitude of the accelerating field spike.

We obtain necessary conditions for the plasma compensation to work in muon colliders. To this end, we analyze the suppression of beam fields by the plasma, collisional diffusion of the return plasma current, possible beam filamentation, and dynamics of plasma ions. We show that a good compensation requires very short beams and allows little freedom in choice of the plasma density.