Investigation of the Way of Phase Synchronization of a Self-Injected Bunch and an Accelerating Wakefield in Solid-State Plasma

Vasyl I Maslov,Denys S Bondar,Ivan N Onishchenko

doi:10.3390/photonics9030174

Abstract

The electron acceleration, in a laser wakefield accelerator, controlled through plasma density inhomogeneity is studied on a basis of 2.5-dimensional particle-in-cell simulation. The acceleration requires a concordance of the density scale length and shift of the accelerated electron bunch relative to wake bubble during electron acceleration. This paper considers the excitation of a wakefield in plasma with a density equal to the density of free electrons in metals, solid-state plasma (the original idea of Prof. T. Tajima), in the context of studying the wakefield process. As is known in the wake process, as the wake bubble moves through the plasma, the self-injected electron bunch shifts along the wake bubble. Then, the self-injected bunch falls into the phase of deceleration of the wake wave. In this paper, support of the acceleration process by maintaining the position of the self-injected electron bunch using an inhomogeneous plasma is proposed. It is confirmed that the method of maintaining phase synchronization proposed in the article by using a nonuniform plasma leads to an increase in the accelerating gradient and energy of the accelerated electron bunch in comparison with the case of self-injection and acceleration in a homogeneous plasma.

Highlights

According to the general principles of wakefield acceleration, when a laser pulse is injected into a plasma, a charge separation is formed and a longitudinal accelerating field is excited
The plasma density must be increased approximately by a factor of four during the time until the self-injected bunch reaches the middle of the wake bubble
3.Conclusions During the study, it was shown that the use of a longitudinally inhomogeneous plasma renders it possible to provide phase synchronization of a self-injected bunch and an accelerating longitudinal wakefield, maintaining the self-injected bunch in the area of During the study, it was shown that the use of a longitudinally inhomogeneous plasma renders it possible to provide phase synchronization of a self-injected bunch and an accelerating longitudinal wakefield, maintaining the self-injected bunch in the area of high accelerating gradient

Summary

Introduction

According to the general principles of wakefield acceleration, when a laser pulse is injected into a plasma, a charge separation is formed and a longitudinal accelerating field is excited. When a wakefield is excited in a solid-state density plasma by an X-ray laser pulse, both an increase in the accelerating gradient and an increase in the density of self-injected bunches are observed. To implement the wakefield acceleration method in a solid-density plasma, new types of lasers are required, which, in many respects, Photonics 2022, 9, 174 excite the wakefield in other environments, for example, by a beam in a dielectric, in which the accelerating gradient 13.8 GV/m is achieved [16]. The plasma density must be increased approximately by a factor of four during the time (at a distance) until the self-injected bunch reaches the middle of the wake bubble. Separate areas in which the ratio of electron injected bunch is close to the middle of the bubble. Separate areas in which the ratio of electron densditeienssriteiaecshreesacahveasluaevoaflu9eaoref h9igarhelighhigtehdliginhtreedd.inPlraesdm. aPellaescmtroaneldeecntrsoitny daenndsiltoyngaintuddlionnagl iatuc-dinal celeraacticneglefriaetlidngdifisterlidbudtiisotrnisb.uxt,ioynasr.exn, yoramrealnizoerdmtaoliλze, dExtoisλn,oErxmiaslnizoerdmtaoliEz0ed= mtoecEω0l/=2πmee.cω /2πe

Results of Simulation

3.Conclusions

Conclusions