NSC/KIPT, Kharkov, Ukraine
The results of the numerical PIC-simulation of accelerated positron bunch focusing in the plasma dielectric wakefield accelerator unit, filled with radially inhomogeneous plasma that has vacuum channel inside are presented. The Wakefield was created by drive electron bunch in quartz dielectric tube with external and internal diameters of 1.2 mm and 1.0 mm, respectively. The tube was embedded in cylindrical metal waveguide. The internal area of dielectric tube has been filled with different transverse density profiles of plasma: homogeneous density and inhomogeneous density created in capillary discharge. Drive bunch electrons energy was 5 GeV, drive bunch charge was 3 nC. The test positron bunch had the same parameters as the drive bunch except for the charge of 0.05 nC. Results of numerical PIC simulation have shown the possibility of simultaneous acceleration and focusing of test positron bunch in the wakefield excited by drive electron bunch. The dependence of transport and acceleration of positron bunch on size of vacuum channel is studied.
NSC/KIPT, Kharkov, Ukraine
A theoretical investigation of a wakefield excitation in a plasma-dielectric accelerating structure by a drive electron bunch in the case of an off-axis bunch injection is carried out. The structure under investigation is a round dielectric-loaded metal waveguide with channel for the charged particles, filled with homogeneous cold plasma. In this paper we focus on the spatial distribution of the bunch-excited wakefield components, which act on both the drive and test bunches, and on transverse bunch dynamics. Dependence of the drive bunch propagation distance on its offset is studied.
NSC/KIPT, Kharkov, Ukraine
To provide experimental researches at the NSC KIPT theoretical studies and computations of the electron acceleration in a dielectric laser accelerator have been carried out. Laser accelerator consists of two periodic quartz structures on diffraction gratings or Chips, symmetrically located along both sides of the vacuum accelerating channel. Using PIC numerical simulations, electromagnetic fields excited by laser radiation with a wavelength of 800 nm in dielectric laser accelerators were investigated. The influence of the shape and depth of the profile of diffraction gratings or Chip structures on the distribution of the electric field in the interaction space has been studied. For modeling, different types of profiles were taken, both in serial and a unique structure. In consequence of the analysis of the obtained results, estimated efficiency of acceleration was defined for each type of profile. The rectangular profile of the diffraction grating with the maximum accelerating gradient was selected as optimal for the next experiments.