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Nonlinear phase dynamics of ideal kink mode in the presence of shear flow

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Plasma Science and Technology 2021年第4期23卷 9-14页

作者：张毅郭志彬 State Key Laboratory of Nuclear Physics and Technology Fusion Simulation CenterSchool of PhysicsPeking UniversityBeijing 100871People’s Republic of China

We investigate nonlinear phase dynamics of an ideal kink mode,induced by E×B flow.Here the phase is the cross phase(θ_(c))between perturbed stream function of velocity(f)and magnetic field(y),i.e.θ_(c)=θf−θψ.A dimensionless parameter,analogous to the R_(i)chardson number,R_(i)=16gkink w^(2)E^(2)(γkink:the normalized growth rate of the pure kink mode;wE:normalized E×B shearing rate)is defined to measure the competition between phase pinning by the current density and phase detuning by the flow shear.When R_(i)>1,θ_(c) is locked to a fixed value,corresponding to the conventional eigenmode solution.When R_(i).1,θ_(c) enters a phase slipping or oscillating state,corresponding to a nonmodal solution.The nonlinear phase dynamics method provides a more intuitive explanation of the complex dynamical behavior of the kink mode in the presence of E×B shear flow.

关键词： kink mode E×B flow nonlinear phase dynamics Richardson number

The Implementation of Magnetic Islands in Gyrokinetic Toroidal Code

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Plasma Science and Technology 2016年第2期18卷 126-130页

作者：江澎林志宏 Ihor HOLOD 肖池阶 Fusion Simulation Center and State Key Laboratory of Nuclear Physics and Technology Peking University Department of Physics and Astronomy University of California

The implementation of magnetic islands in gyrokinetic simulation has been verified in the gyrokinetic toroidal code(GTC).The ion and electron density profiles become partially flattened inside the islands.The density profile at the low field side is less flattened than that at the high field side due to toroidally trapped particles in the low field side,which do not move along the perturbed magnetic field lines.When the fraction of trapped particles decreases,the density profile at the low field becomes more flattened.

关键词：等离子体超声波注射剂分子组织

Integrated guidance and control design method based on finite-time state observer

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Journal of Systems Engineering and Electronics 2018年第6期29卷 1251-1262页

作者： MA Ping ZHANG Denghui WANG Songyan CHAO Tao Control and simulation center Harbin Institute of Technology

A composited integrated guidance and control(IGC) algorithm is presented to tackle the problem of the IGC design in the dive phase for the bank-to-turn(BTT) vehicle with the inaccuracy information of the line-of-sight(LOS) rate. For the sake of theoretical derivation, an IGC model in the pitch plane is established. The high-order finite-time state observer(FTSO), with the LOS angle as the single input, is employed to reconstruct the states of the system online. Besides, a composited IGC algorithm is presented via the fusion of back-stepping and dynamic inverse. Compared with the traditional IGC algorithm, the proposed composited IGC method can attenuate effectively the design conservation of the flight control system, while the LOS rate is mixed with noise. Extensive experiments have been performed to demonstrate that the proposed approach is globally finite-time stable and strongly robust against parameter uncertainty.

关键词： integrated guidance and control(IGC) finite-time state observer(FTSO) back-to-turn(BTT)vehicle composited control

GTC simulation of Ideal Ballooning Mode in Tokamak Plasmas

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Plasma Science and Technology 2013年第6期15卷 499-505页

作者：李泽彬孙国亚 Ihor HOLOD 肖湧张文禄林志宏 Department of Physics and Institute of Theoretical Physics and Astrophysics Xiamen University Department of Physics and Astronomy University of CaliforniaIrvineCalifornia 92697USA Institute of fusion Theory and simulation Zhejiang University CAS Key Laboratory of Basic Plasma Physics University of Science and Technology of China Department of Physics and Astronomy University of California Fusion Simulation Center Peking University

In the present paper,we first derive the eigenmode equation of the ideal ballooning mode in tokamak plasmas using a gyrokinetic equation.It is shown that the gyrokinetic eigenmode equation can be reduced to the magnetohydrodynamic(MHD) form in the long wavelength limit when kinetic effects are ignored.Then,the global gyrokinetic toroidal code(GTC) is applied for simulations of the edge-localized ideal ballooning modes.The obtained mode structures are compared with the results of ideal MHD simulations.The observed scaling of the linear growth rate with the toroidal mode number is consistent with the ideal MHD theory.The simulation results verify the GTC capability of simulating MHD processes in toroidal plasmas.

关键词：托卡马克等离子体模拟应用气球模 GTC 理想动力学方程回旋动力学环形等离子体

Radiation Hydrodynamic simulations in the Planar Scheme for the Fundamental Studies of Shock Ignition

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Plasma Science and Technology 2016年第4期18卷 376-381页

作者：董云松杨家敏宋天明朱托黄成武 Department of Experimental Physics Laser Fusion Research Center

As a fundamental and crucial research topic in the direct-driven inertial confinement fusion(ICF),especially for shock ignition(SI),investigation on the laser coupling with planar lowZ targets is beneficial for deep physical comprehension at the primary phase of SI.The production of the intense shock and the shock coalescence in the multi-layer targets,driven by the 3ω intense laser(351 nm the wavelength),were studied in detail with the 1D and 2D radiation hydrodynamic simulations.It was inferred that the 1D simulation would overrate the shock velocity and the ablation pressure of the spike;the coalescence time and the velocity of the coalescence shock depended evidently on the pulse shape and the start time of the spike.The present study can also provide a semi-quantitative reference for the design of the SI decomposition experiments on the Shenguang-III prototype laser facility.

关键词：激波点火二维辐射流体动力学模拟基础研究惯性约束聚变流体力学模拟冲击速度开始时间

基于晶体塑性的辐照金属材料局部化颈缩和吕德斯带的模拟研究

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Acta Mechanica Sinica 2023年第4期39卷 132-146页

作者：付家琪刘文斌隋昊男程杨洋段慧玲 State Key Laboratory for Turbulence and Complex System Department of Mechanics and Engineering ScienceThe Beijing Innovation Center for Engineering Science and Advanced TechnologyCollege of EngineeringPeking UniversityBeijing100871China Key Laboratory of High Energy Density Physics simulation Center for Applied Physics and Technologyand Inertial Fusion Sciences and ApplicationsCollaborative Innovation Center of Ministry of EducationPeking UniversityBeijing100871China

金属材料中,颈缩失稳通常由表面缺陷或材料不均匀性等潜在扰动引起并随着微结构的演化进一步发展.本文将构型扰动法与考虑辐照效应的晶体塑性本构关系相结合,模拟了辐照前后局部化颈缩和吕德斯带等现象.通过考虑模拟局部化变形中扰动的... 详细信息

金属材料中,颈缩失稳通常由表面缺陷或材料不均匀性等潜在扰动引起并随着微结构的演化进一步发展.本文将构型扰动法与考虑辐照效应的晶体塑性本构关系相结合,模拟了辐照前后局部化颈缩和吕德斯带等现象.通过考虑模拟局部化变形中扰动的必要性,发现了外在的几何缺陷和内禀的微结构演化在颈缩过程中的竞争关系.此外,以纯金属铜和奥氏体不锈钢为例研究了辐照硬化效应对颈缩失稳的影响.结果表明,流动应力的增加和功硬化能力的降低是均匀延伸率下降的原因,辐照效应导致的织构软化作用可以忽略.为了解释辐照后低碳钢下屈服点和吕德斯应变同时增加的现象,一种位错脱钉扎和位错与辐照缺陷的交互作用相耦合的塑性变形机制被提出并结合修正的流动方程,很好地模拟出包含屈服下降、应力平台、应变扩展和应变硬化等特征的吕德斯带现象.其中,位错与辐照缺陷的相互作用也可以解释辐照后纯金属材料中发现的扩散颈缩现象.我们的模拟结果既阐明了几何缺陷在颈缩失稳中的重要作用,也为辐照金属中常见的宏观塑性失稳现象提供了清晰的物理图像.

关键词：吕德斯带金属材料奥氏体不锈钢晶体塑性下屈服点流动应力几何缺陷均匀延伸率

Continued Study on Hohlraum Radiation Source with Approximately Constant Radiation Temperature

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Plasma Science and Technology 2016年第4期18卷 342-345页

作者：宋天明杨家敏朱托李志超黄成武 Laser fusion Research center Mianyang 621900 China

An experiment was performed on the Shenguang III prototype laser facility to continue the study on hohlraum radiation source with approximately constant radiation temperature using a continuously shaped laser pulse.A radiation source with a flattop temperature of about130 e V that lasted about 5 ns was obtained.The previous analytical iteration method based on power balance and self-similar solution of ablation was modified taking into account the plasma movements and it was used to design the laser pulse shape for experiment.A comparison between experimental results and simulation is presented and better agreement was achieved using the modified method.Further improvements are discussed.

关键词：辐射温度辐射源黑腔恒定激光装置等离子体运动迭代方法自相似解

Generation of Alfvén wave energy during magnetic reconnection in Hall MHD

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Plasma Science and Technology 2017年第10期19卷 5-13页

作者：李灵杰马志为王理程 Institute for fusion Theory and simulation Zhejiang University

The effect of the reconnection rate on the generation of Alfvén wave energy is systematically investigated using Hall magnetohydrodynamics(MHD). It is well known that a decrease in magnetic energy is proportional to the reconnection rate. It is found that an instantaneous increase in Alfvén wave energy in unit Alfvén time is the square dependence on the reconnection rate. The converted Alfvén wave energy is strongly enhanced due to the large increase in the reconnection rate in Hall MHD. For solar-terrestrial plasmas, the maximum converted Alfvén wave energy in unit Alfvén time with the Hall effect can be over 50 times higher than that without the Hall effect during magnetic reconnection.

关键词：能量系统磁重联 MHD 磁流体发电等离子体霍尔效应单元地球

The Calibration of the DD Neutron Indium Activation Diagnostic

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Plasma Science and Technology 2015年第4期17卷 337-339页

作者：宋仔峰陈家斌刘中杰詹夏宇唐琦 Research center of Laser fusion China Academy of Engineering Physics

The indium activation diagnostic was calibrated using an accelerator neutron source to facilitate the diagnosis of deuterium-deuterium(DD)neutron yields of implosion experiments in the Shenguang-III facility.The scattered neutron background of the accelerator room was measured by placing a polypropylene shadow bar in front of the indium sample,so as to correct the calibrated factor of this activation diagnostic.The proper size of the shadow bar was given by Monte Carlo simulation.The calibration results showed that the scattered neutron background of the accelerator room was about 9%of the incident neutrons on the sample.Subtracting the portion induced by the neutron background,the calibrated factor for this sample condition was4.52×10^(-7)counts/n with an uncertainty of 4.3%.

关键词：中子活化诊断标定铟校准因子蒙特卡洛模拟加速器内爆实验