Search

We study the propagation of a relativistic ultrashort laser pulse in two-dimensional inhomogeneous plasma with a density ripple based on the theoretical analysis and the particle-in-cell simulation. An analytical solution of the laser pulse propagating in the homogeneous plasma is completely obtained. It is found that the stable propagation of the relativistic ultrashort laser pulse in homogeneous plasma can be realized, and the propagation distance and intensity of the laser pulse and the spatial distribution of electron density can be effectively modulated by adjusting the pulsewidth of the incident laser and the plasma frequency. More interestingly, in the inhomogeneous plasma with a density ripple, when the wave amplitude of the density ripple is less than a critical value, the intensity of the ultrashort laser pulse is almost unchanged and the propagation characteristics of the laser in the inhomogeneous plasma are basically consistent with those in the homogeneous plasma. However, when the wave amplitude of the density ripple is larger than the critical value, the inhomogeneity of the plasma has an obvious effect on the laser characteristics, and the intensity and the spatial distribution of the laser pulse will be modulated by the plasma density ripple. The influence of the laser pulsewidth, plasma density, and plasma density ripple on the laser characteristics is discussed in detail. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The effects of super-Gaussian chirped laser pulse and inhomogeneity of plasma on space distribution and amplitude of wakefield are studied. The different super-Gaussian chirped laser pulse envelopes are used to strike the uniform and various inhomogeneous plasmas. The results show that compared with the unchirped laser pulse, the chirped laser pulse can enhance the wakefield generation, make the bubbles’ structure deformative seriously, reduce the numbers of bubbles in the same longitudinal distance, and enlarge the size of the wakefield bubbles. Besides, the stronger wakefield is generated in inhomogeneous plasma compared with a uniform one. Moreover, the characteristics of the wakefield can be controlled efficiently by the super-Gaussian pulse index. That is, the amplitude and spatial structure of the plasma wakefield can be modulated by the super-Gaussian chirped laser pulse and the inhomogeneity of the plasma. [ABSTRACT FROM AUTHOR]