检索结果-南通市图书馆

Time-Resolved Transmission Measurements of Warm Dense Iron Plasma

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2016年第3期33卷 64-67页

作者：青波赵阳韦敏习黎航熊刚吕敏胡智民张继彦杨家敏 Research center of Laser fusion China Academy of Engineering Physics

Transmission measurements of warm dense iron plasma are reported over the photon energy range of 400-1200 e V, including the strong 2p-3d structures. One-dimensional hydrodynamic simulation is performed to estimate the plasma conditions： temperatures of several eV and densities of about O. 1 g/cm3. By using the simulated tempera- ture and density, the calculations of the transmission spectra are performed and compared with the time-resolved experimental results.

关键词： of as is in Time-Resolved Transmission Measurements of Warm Dense Iron Plasma were

The Calibration of the DD Neutron Indium Activation Diagnostic

在线全文

学校读者我要写书评

暂无评论

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： indium activation shadow bar Monte Carlo simulation

Nonlinear excitation of a geodesic acoustic mode by reversed shear Alfvén eignemodes

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2022年第2期24卷 57-61页

作者：王亚辉王涛魏士朝仇志勇 Institute for fusion Theory and simulation and Department of Physics Zhejiang UniversityHangzhou 310027People's Republic of China center for Nonlinear Plasma Science and ENEA C.R.Frascati Frascati 65-00044Italy

The parametric decay process of a reversed shear Alfvén eigenmeode(RSAE)into a geodesic acoustic mode and a kinetic RSAE is investigated using nonlinear gyrokinetic theory.The excitation conditions mainly require the pump RSAE amplitude to exceed a certain threshold,which could be readily satisfied in burning plasmas operated in steady-state advanced scenario.This decay process can contribute to thermal plasma heating and confinement improvement.

关键词： reversed shear Alfvén eigenmode geodesic acoustic mode gyrokinetic theory nonlinear mode coupling burning plasmas alpha channelling

Single order soft X-ray diffraction with quasi-random radius pinhole array spectroscopic photon sieves

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2014年第4期23卷 342-346页

作者：张强强魏来杨祖华钱凤范全平张博谷渝秋曹磊峰 Research center of Laser fusion China Academy of Engineering Physics

A novel single order diffraction grating in the soft X-ray region, called quasi-random radius pinhole array spectro- scopic photon sieves （QRSPS）, is proposed in this paper. This new grating is composed of pinholes on a substrate, whose radii are quasi-random, while their centers are regular. Analysis proves that its transmittance function across the grating bar is similar to that of sinusoidal transmission gratings. simulation results show that the QRSPS can suppress higher-order diffraction effectively. And the QRSPS would still retain its characteristic of single order diffraction when we take the effect of X-ray penetration into account. These properties indicate that the QRSPS can be used in the soft X-ray spectra measurement.

关键词： diffraction properties diffraction gratings soft X-rays single-order diffraction

The intermittent excitation of geodesic acoustic mode by resonant Instanton of electron drift wave envelope in L-mode discharge near tokamak edge

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2022年第4期31卷 449-467页

作者：刘朝阳章扬忠 Swadesh Mitter Mahajan 刘阿娣周楚谢涛 Institute for fusion Theory and simulation and Department of Physics Zhejiang UniversityHangzhou 310027China center for Magnetic fusion Theory Chinese Academy of SciencesHefei 230026China Institute for fusion Studies University of Texas at AustinAustinTexas 78712USA School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230026China School of Science Sichuan University of Science and EngineeringZigong 643000China

There are two distinct phases in the evolution of drift wave envelope in the presence of zonal flow.A long-lived standing wave phase,which we call the Caviton,and a short-lived traveling wave phase(in radial direction) we call the Instanton.Several abrupt phenomena observed in tokamaks,such as intermittent excitation of geodesic acoustic mode(GAM) shown in this paper,could be attributed to the sudden and fast radial motion of Instanton.The composite drift wave-zonal flow system evolves at the two well-separate scales:the micro-scale and the meso-scale.The eigenmode equation of the model defines the zero-order(micro-scale) variation;it is solved by making use of the two-dimensional(2 D) weakly asymmetric ballooning theory(WABT),a theory suitable for modes localized to rational surface like drift waves,and then refined by shifted inverse power method,an iterative finite difference method.The next order is the equation of electron drift wave(EDW) envelope(containing group velocity of EDW) which is modulated by the zonal flow generated by Reynolds stress of EDW.This equation is coupled to the zonal flow equation,and numerically solved in spatiotemporal representation;the results are displayed in self-explanatory graphs.One observes a strong correlation between the Caviton-Instanton transition and the zero-crossing of radial group velocity of EDW.The calculation brings out the defining characteristics of the Instanton:it begins as a linear traveling wave right after the transition.Then,it evolves to a nonlinear stage with increasing frequency all the way to 20 kHz.The modulation to Reynolds stress in zonal flow equation brought in by the nonlinear Instanton will cause resonant excitation to GAM.The intermittency is shown due to the random phase mixing between multiple central rational surfaces in the reaction region.

关键词： zonal flow drift wave Instanton L-H mode

PDRK:A General Kinetic Dispersion Relation Solver for Magnetized Plasma

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2016年第2期18卷 97-107页

作者：谢华生肖湧 Institute for fusion Theory and simulation and the Department of Physics Zhejiang University

A general,fast,and effective approach is developed for numerical calculation of kinetic plasma linear dispersion relations.The plasma dispersion function is approximated by J-pole expansion.Subsequently,the dispersion relation is transformed to a standard matrix eigenvalue problem of an equivalent linear system.Numerical solutions for the least damped or fastest growing modes using an 8-pole expansion are generally accurate;more strongly damped modes are less accurate,but are less likely to be of physical interest.In contrast to conventional approaches,such as Newton＇s iterative method,this approach can give either all the solutions in the system or a few solutions around the initial guess.It is also free from convergence problems.The approach is demonstrated for electrostatic dispersion equations with one-dimensional and twodimensional wavevectors,and for electromagnetic kinetic magnetized plasma dispersion relation for bi-Maxwellian distribution with relative parallel velocity flows between species.

关键词： plasma physics dispersion relation kinetic waves instabilities linear system matrix eigenvalue

Laser-driven flier impact experiments at the SG-III prototype laser facility

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2015年第9期24卷 319-323页

作者：税敏储根柏辛建婷吴玉迟朱斌何卫华席涛谷渝秋 Science and Technology on Plasma Physics Laboratory Research Center of Laser FusionCAEP

Laser-driven flier impact experiments have been designed and performed at the SG-III prototype laser facility. The continuum phase plate（CPP） technique is used for the 3 ns quadrate laser pulse to produce a relatively uniform irradiated spot of 2 mm. The peak laser intensity is 2.7×10^13W/cm^2 and it accelerates the aluminum flier with a density gradient configuration to a high average speed of 21.3 km/s, as determined by the flight-of-time method with line VISAR. The flier decelerates on impact with a transparent silica window, providing a measure of the flatness of the flier after one hundred microns of flight. The subsequent shock wave acceleration, pursuing, and decay in the silica window are interpreted by hydrodynamic simulation. This method provides a promising method to create unique conditions for the study of a material＇s properties.

关键词： laser-driven flier,VISAR,shock wave

Space-Resolved Spectrum Diagnose by Soft X-Ray Transmission Grating Spectrometer

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2011年第1期13卷 36-39页

作者：尚万里赵阳熊刚杨家敏朱托 Research center of Laser fusion China Academy of Engineering Physics

A space-resolving transmission grating spectrometer is established on the ＂Shenguang-III＂ prototype laser facility and an iterative procedure for unfolding the X-ray spectrum with spatial resolution is described. The diagnostics is applied to measure the X-ray spectrum from laser-entered gold target and the typical space-resolved spectrum is provided. The relative standard uncertainty of the X-ray spectrum from the laser-generated plasma is also determined.

关键词： transmission grating spectrometer numerical simulation spectrum diagnose

Longitudinal Flight Dynamic Analysis on Vertical Takeoff of a Tailless Flapping-Wing Micro Air Vehicle

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2018年第2期15卷 283-297页

作者： Loan Thi Kim Au Vu Hoang Phan Hoon Cheol Park Department of Advanced Technology fusion and Artificial Muscle Research center Konkuk University Seou105029 Korea

This paper first analyzed the longitudinal dynamic behavior during vertical takeoff without control of a Flapping-Wing Micro Air Vehicle （FW-MAV）. The standard linear flight dynamics based on small disturbances from trim condition was not applicable for our analysis because the initial flight condition, which was at rest on the ground, could be such a large disturbance from the trim condition that the linearization is invalid. Therefore, we derived linearized Equations of Motion （EoM） which can treat an untrimmed flight condition as a reference for disturbances. The Computational Fluid Dynamic （CFD） software ANSYS Fluent was used to compute the aerodynamic forces and pitching moments. Three flight modes were found： a fast subsidence mode, a slow subsidence mode and a divergence oscil- latory mode. Due to divergence oscillatory mode, the deviation from the reference flight grew with time; the FW-MAV tumbled without control. The simulation showed for the first 0.5 second after leaving the ground （the time that is long enough for delay of feedback control）, the FW-MAV flew up to a height of 6 cm with small horizontal and pitching motion, which is close to a vertical flight.

关键词： bioinspired FW-MAV flight dynamics vertical takeoff CFD linear theory