Three-dimensional particle-in-cell simulations of beam self-modulation and external injection in plasma wake field acceleration

该项目旨在模拟长等离子体柱中质子束自调制和高能加速尾流场激发的全三维粒子池（PIC）模拟。这些模拟是为了支持欧洲核子研究中心（CERN）先进韦克菲尔德（Advanced WAKEfield）实验的“RUN 2”阶段，该阶段利用等离子体中长质子束的自调制。目前，我们的粒子池（PIC）代码的准静态版本VLPL（虚拟激光等离子体实验室）被几个研究小组用来模拟未简化的AWAKE条件。AWAKE的RUN 2阶段将使用分段等离子体腔和纵向定制的等离子体剖面来优化尾流结构。全三维几何图形的PIC模拟（包括准静态和电磁的）对于理解激发态尾流场的径向对称性和见证束加速度的可实现质量至关重要。为了将模拟速度提高一个数量级或更多，我们将在3D圆柱形几何中实现我们的代码，并根据笛卡尔几何对其进行测量。

The project is aimed at full three-dimensional Particle-in-Cell (PIC) simulations of proton bunch self-modulation in long plasma columns and wake field excitation for high energy acceleration. The simulations are to support the "RUN 2" phase of AWAKE (Advanced WAKEfield) experiment at CERN that exploits self-modulation of a long proton bunch in plasma. Presently, the quasi-static version of our particle-in-cell (PIC) code VLPL (Virtual Laser-Plasma Lab) is used by several groups to simulate the unabridged AWAKE conditions. The RUN 2 phase of AWAKE will use staged plasma cavities and longitudinally tailored plasma profile to optimize the wake structure. The PIC simulations in the full 3D geometry – both quasistatic and electromagnetic ones – are crucial to understand radial symmetry of the excited wake field and the achievable quality of the witness bunch acceleration. To speed up the simulations by an order of magnitude or more, we are going to implement our code in 3D cylindrical geometry and gauge it against the Cartesian geometry.