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Please wait a minute... For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select Study on Extreme Plasma Dynamics by Quantum Electrodynamic Particle-in-Cell Simulations CHANG Hengxin, XU Zheng, YAO Weipeng, XIE Yu, QIAO Bin CHINESE JOURNAL OF COMPUTATIONAL PHYSICS    2017, 34 (5): 526-542.   Abstract （1036）   HTML （25）    PDF （4769KB）（3484）       Knowledge map    Next generation petawatt laser facility is expected to reach intensity up to the order of 1023-1024 W·cm-2,which may generate electromagnetic fields so strong that nonlinear quantum electrodynamics (QED) processes play a crucial role in plasma dynamics.A large number of γ photons can be emitted through synchrotron radiation from ultrarelativistic electrons,and pair creation process can also be triggered when γ photons traverse electromagnetic fields.In turn,these QED physics can affect plasma dynamics itself significantly,in particular for electron motion under radiation reaction.In order to study such extreme plasma dynamics,we introduce a QED model developed in recent years,which can be coupled with traditional particle-in-cell (PIC) code,i.e.,so-called a QED-PIC code.Due to booming particle number caused by the newly emitted photons and created pairs,we also develop a particle merge algorithm to reduce the computational scale.Several applications of this contemporary QED-PIC code in modeling of ultraintense laser-plasma interaction and extreme astrophysical phenomena are presented. Reference | Related Articles | Metrics Select Numerical Method for Relativistic Vlasov Equation in Cartesian-Spherical Coordinate System ZHANG Hua, WU Sizhong, ZHOU Cangtao, HE Minqing, CAI Hongbo, CAO Lihua, ZHU Shaoping, HE Xiantu CHINESE JOURNAL OF COMPUTATIONAL PHYSICS    2017, 34 (5): 543-554.   Abstract （641）   HTML （1）    PDF （2635KB）（1475）       Knowledge map    We study numerical method for relativistic Vlasov equation and present a scheme for computing Vlasov equation based on Cartesian-spherical coordinate system, which can be used to reduce number of numerical grid for momentum space. Furthermore, a 4th order non-splitting finite volume scheme is proposed in order to solve momentum parts of relativistic Vlasov equation. In test problems, especially relativistic Landau problem, laser-plasma interaction are solved by using the scheme. We confirm the scheme with theoretically analysis as well as numerical comparison with results of PIC method. Reference | Related Articles | Metrics Select Hybrid Particle-in-Cell/Fluid Model for Hot Electron Transport in Dense Plasmas XU Han, ZHUO Hongbin, YANG Xiaohu, HOU Yong, YIN Yan, LIU Jie CHINESE JOURNAL OF COMPUTATIONAL PHYSICS    2017, 34 (5): 505-525.   Abstract （625）   HTML （16）    PDF （2828KB）（3084）       Knowledge map    One of key issues in high energy density physics is clarification of transport and energy deposition of laser-produced fast electrons traveled through dense plasma. However, modeling these systems numerically is still a great challenge. In this paper, we introduce a PIC/fluid hybrid model. In this hybrid method, fast electrons are modeled by a relativistic Fokker-Planck equation, which numerically solved by reducing it to equivalent stochastic differential equations. Background electrons and ions are treated as two-fluid model. Collisions, electric and magnetic fields, and evolutions of resistivity due to heating of background are included. Treatment is valid for fast electron number densities much less than that of background, fast electron energies much greater than background temperature, and time scales short enough that magnetic diffusion and thermal conduction can be negligible. Model of ionization and resistivity also determine validity of the model. Reference | Related Articles | Metrics Select A Fast Box Set Subtraction Algorithm for Parallel Structured Adaptive Mesh Refinement Applications LIU Xu, XU Xiaowen, ZHANG Aiqing CHINESE JOURNAL OF COMPUTATIONAL PHYSICS    2017, 34 (5): 563-573.   Abstract （567）   HTML （0）    PDF （3124KB）（1340）       Knowledge map    Box set subtraction is widely used in SAMR to compute data dependency and nested restriction. Traditional box set subtraction algorithms suffer from high time complexity, which often dominates execution time for large scale SAMR simulations. In this paper, a divide and conquer box set subtraction algorithm with linear time complexity was proposed, and enhanced by domain decomposition parallelization. Experiment results on regular box set and irregular box set of SAMR application verify linear time complexity property. And for large scale problems, our algorithm shows great improvement on computing time. Reference | Related Articles | Metrics