Wakefield generation by chirped super-Gaussian laser pulse in inhomogeneous plasma

We study the effect of nonlinearly chirped super-Gaussian （SG） laser pulse on wakefield generation in an inhomogeneous plasma. The different types of nonlinearly chirped pulse are employed, and different kinds of inhomogeneous plasma density are used. The maximum wakefield amplitude as the function of nonlinearly chirped laser pulse and inhomogeneous plasma density in parameter space are obtained. Moreover, the dependence of the maximum wakefield amplitude on the SG laser pulse index is discussed. This shows that a larger wakefield can be obtained when the chirped pulse and inhomogeneous density are in the critical regions. Wakefield generation can be controlled by adjusting the chirped SG pulse and inhomogeneous plasma density parameters. That is, we provide an efficient way for the controlled generation of the wakefield.

Direct electron acceleration by chirped laser pulse in a cylindrical plasma channel

We study the dynamics of single electron in an inhomogeneous cylindrical plasma channel during the direct acceleration by linearly polarized chirped laser pulse.By adjusting the parameters of the chirped laser pulse and the plasma channel,we obtain the energy gain,trajectory,dephasing rate and unstable threshold of electron oscillation in the channel.The influences of the chirped factor and inhomogeneous plasma density distribution on the electron dynamics are discussed in depth.We find that the nonlinearly chirped laser pulse and the inhomogeneous plasma channel have strong coupled influence on the electron dynamics.The electron energy gain can be enhanced,the instability threshold of the electron oscillation can be lowered,and the acceleration length can be shortened by chirped laser,while the inhomogeneity of the plasma channel can reduce the amplitude of the chirped laser.