无涡冷等离子体中的二维定常尾流场。I

Wake excited in plasma by an ultra-relativistic point-like bunch

A plasma flow behind a relativistic electron bunch propagating through a cold plasma is found assuming that the transverse and longitudinal dimensions of the bunch are small and the bunch can be treated as a point charge. In addition, the bunch charge is assumed small. A simplified system of equations for the plasma electrons is derived and it is shown that, through a simple rescaling of variables, the bunch charge can be eliminated from the equations. These equations have a unique solution, with an ion cavity formed behind the driver. The equations are solved numerically and the scaling of th…

等离子体泡场中的稳定电子涡旋态

Stationary electron vortex states in a plasma bubble field

该研究针对等离子体尾场加速器，通过求解准相对论薛定谔方程获得电子涡旋态的解析解，验证了等离子体泡可稳定约束涡旋电子，为其后续加速研究提供了基础。

等离子体中温束流的尾场驱动丝化

Wakefield-driven filamentation of warm beams in plasma

本文建立了有限尺寸温束流的三维时空双流理论，揭示有限发射度扩散引入主导波数和截止波数，并经相对论电子-正电子束流PIC模拟验证，深化了对等离子体加速器中束流丝化机制的理解。

Improved Numerical Method for Solution of the Haïssinski Equation

The longitudinal charge density of an electron beam in its equilibrium state is given by the solution of the Haïssinski equation, which provides a stationary solution of the Vlasov-Fokker-Planck equation. The physical input is the longitudinal wake potential. We formulate the Haïssinski equation as a nonlinear integral equation with the normalization integral stated as a functional of the solution. This equation can be solved in a simple way by the matrix version of Newtons's iteration, beginning with the Gaussian as a first guess. We illustrate for several quasi-realistic wake potentials. Con…

等离子体中相对论束激发电磁尾场的理论分析与PIC模拟

Theoretical Analysis and PIC Simulations of Electromagnetic Wakefields Excited by Relativistic Beams in Magnetized Plasmas

本文研究了强磁场中超相对论电子束在冷等离子体通道中激发的纵向和径向尾场，通过发展三维格林函数形式主义并结合PIC模拟，验证了磁场对尾场振荡特性的影响。

Non-linear Ion-Wake Excitation by the Time-Asymmetric Electron Wakefields of Intense Energy Sources with applications to the Crunch-in regime

A model for the excitation of a non-linear ion-wake mode by a train of plasma electron oscillations in the non-linear time-asymmetric regime is developed using analytical theory and particle-in-cell based computational solutions. The ion-wake is shown to be a driven non-linear ion-acoustic wave in the form of a cylindrical ion-soliton. The near-void and radially-outwards propagating ion-wake channel of a few plasma skin-depth radius, is explored for application to "Crunch-in" regime of positron acceleration. The coupling from the electron wakefield mode to the ion-mode dictates the long-term e…

Attosecond-Angstrom free-electron-laser towards the cold beam limit

Electron beam quality is paramount for X-ray pulse production in free-electron-lasers (FELs). State-of-the-art linear accelerators (linacs) can deliver multi-GeV electron beams with sufficient quality for hard X-ray-FELs, albeit requiring km-scale setups, whereas plasma-based accelerators can produce multi-GeV electron beams on metre-scale distances, and begin to reach beam qualities sufficient for EUV FELs. We show, that electron beams from plasma photocathodes many orders of magnitude brighter than state-of-the-art can be generated in plasma wakefield accelerators (PWFA), and then extracted,…

Accelerated Ions from a Laser Driven Z-pinch

Intense laser acceleration of ions is inherently difficult due to the velocity mismatch between laser pulses moving at the speed of light and slowly moving massive ions. Instead of directly accelerating the ions, current approaches rely on TV/m laser fields to ionize and drive out electrons. The ions are then accelerated by the resulting electrostatic fields from charge separation. Here we report experimental and numerical acceleration of ions by means of laser driven Z-pinch exiting a sharp plasma interface. This is achieved by first driving a plasma wakefield in the self-modulated bubble reg…