Modeling of laser wakefield acceleration in Lorentz boosted frame using EM-PIC code with spectral solver

JOURNAL OF COMPUTATIONAL PHYSICS

卷:266

Article

Yu, Peicheng¹  Xu, Xinlu²  Decyk, Viktor K.³  An, Weiming¹  Vieira, Jorge⁴  Tsung, Frank S.³  Fonseca, Ricardo A.^4,5  Lu, Wei²  Silva, Luis O.⁴  Mori, Warren B.^1,3 

[1] Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA

[2] Tsinghua Univ, Dept Engn Phys, Beijing 100084, Peoples R China

[3] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA

[4] Inst Super Tecn, Lisbon, Portugal

[5] ISCTE Inst Univ Lisboa, P-1649026 Lisbon, Portugal

关键词: Particle-in-cell;    Plasma simulation;    Laser wakefield accelerator;    Boosted frame simulation;    Spectral solver;    Numerical Cerenkov instability;   

DOI  :  10.1016/j.jcp.2014.02.016

来源: Elsevier

【 摘 要 】

Simulating laser wakefield acceleration (LWFA) in a Lorentz boosted frame in which the plasma drifts towards the laser with nu(b) can speed up the simulation by factors of gamma(2)(b) = (1 nu(2)(b)/c(2))(-1). In these simulations the relativistic drifting plasma inevitably induces a high frequency numerical instability that contaminates the interesting physics. Various approaches have been proposed to mitigate this instability. One approach is to solve Maxwell equations in Fourier space (a spectral solver) as this has been shown to suppress the fastest growing modes of this instability in simple test problems using a simple low pass or ring or shell like filters in Fourier space. We describe the development of a fully parallelized, multi-dimensional, particle-in-cell code that uses a spectral solver to solve Maxwell's equations and that includes the ability to launch a laser using a moving antenna. This new EM-PIC code is called UPIC-EMMA and it is based on the components of the UCLA PIC framework (UPIC). We show that by using UPIC-EMMA, LWFA simulations in the boosted frames with arbitrary yb can be conducted without the presence of the numerical instability. We also compare the results of a few LWFA cases for several values of yb, including lab frame simulations using OSIRIS, an EM-PIC code with a finite-difference time domain (FDTD) Maxwell solver. These comparisons include cases in both linear and nonlinear regimes. We also investigate some issues associated with numerical dispersion in lab and boosted frame simulations and between FDTD and spectral solvers. (C) 2014 Elsevier Inc. All rights reserved.

【 授权许可】

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