The process of multistage acceleration of polarised electrons in the wakefield of a relativistic femtosecond laser pulse is investigated. The main mechanism of the growth of slice emittance for a moderately nonlinear regime of laser-plasma acceleration is demonstrated. The main conditions for setting the initial parameters of the electron bunch are determined, which allow minimising the mixing of the phases of betatron oscillations of particles in the bunch slice and the emittance growth during acceleration. The method of smooth input of an electron bunch into the accelerating stage and its smooth removal from this stage is studied, which allows the main characteristics of the bunch to be preserved, such as emittance and polarisation, for further particle transportation and acceleration. The effect of the radiation friction force and the radiation polarisation mechanism on the process of particle depolarisation in acceleration to energies of ∼4 TeV in model fields characteristic of moderately nonlinear and strongly nonlinear regimes of laser-plasma acceleration is considered.

研究了相对论飞秒激光脉冲尾场中极化电子的多级加速过程。演示了激光等离子体加速的适度非线性状态下切片发射率增长的主要机制。确定了设置电子束初始参数的主要条件，这使得束切片中粒子的电子加速器振荡相位的混合和加速过程中的发射率增长最小化。研究了将电子束平滑输入加速级并从该级平滑移出的方法，该方法可以保留电子束的主要特性，例如发射率和极化率，以便进一步进行粒子传输和加速。