Polarization rotation of a probe pulse by the target is observed with the Faraday rotation method in the interaction of an intense laser pulse with a solid target. The rotation of the polarization plane of the probe p...Polarization rotation of a probe pulse by the target is observed with the Faraday rotation method in the interaction of an intense laser pulse with a solid target. The rotation of the polarization plane of the probe pulse may result from a combined action of fused silica and diffused electrons. After the irradiation of the main pulse, the rotation angle changed significantly and lasted ~2 ps. These phenomena may imply a persistent magnetic field inside the target. An analytical model is developed to explain the experimental observation. The model indicates that a strong toroidal magnetic field is induced by an energetic electron beam. Meanwhile, an ionization channel is observed in the shadowgraph and extends at the speed of light after the irradiation of the main beam. The formation of this ionization channel is complex, and a simple explanation is given.展开更多
A magnetohydrodynamic （MHD） power generator system involves several subjects such as magnetohydrodynamics, plasma physics, material science, and structure mechanics. Therefore, the performance of the MHD power gener...A magnetohydrodynamic （MHD） power generator system involves several subjects such as magnetohydrodynamics, plasma physics, material science, and structure mechanics. Therefore, the performance of the MHD power generator is affected by many factors, among which the load coefficient k is of great importance. This paper reveals the effect of some system parameters on the performance by three-dimensional （3D） numerical simulation for a Faraday type MHD power generator using He/Xe as working plasma. The results show that average electrical conductivity increases first and then decreases with the addition of magnetic field intensity. Electrical conductivity reaches the maximum value of 11.05 S/m, while the applied magnetic field strength is B = 1.75 T. When B 〉 3 T, the ionization rate along the midline well keeps stable, which indicates that the ionization rate and three-body recombination rate （three kinds of particles combining to two kinds of particles） are approximately equal, and the relatively stable plasma structure of the mainstream is preserved. Efficiency of power generation of the Faraday type channel increases with an increment of the load factor. However, enthalpy extraction first increases to a certain value, and then decreases with the load factor. The enthalpy extraction rate reaches the maximum when the load coefficient k equals 0.625, which is the best performance of the power generator channel with the maximum electricity production.展开更多
针对单层过渡金属硫化物(transition metal dichalcogenides,TMDC)绝对磁光效应弱,影响了其在磁光装置中的实际应用的问题,提出了3种由单层TMDC和SiC组成的复合结构,通过传输矩阵法分别计算了它们的法拉第旋转(Faraday rotation,FR)角...针对单层过渡金属硫化物(transition metal dichalcogenides,TMDC)绝对磁光效应弱,影响了其在磁光装置中的实际应用的问题,提出了3种由单层TMDC和SiC组成的复合结构,通过传输矩阵法分别计算了它们的法拉第旋转(Faraday rotation,FR)角和透过率。研究结果表明:3种复合结构均能实现磁光性能的改善;相对于单层TMDC与SiC基底组成的双层结构,对称复合结构在工作频率处获得了8倍的FR角增强和0.8的透过率;且复合结构还实现了一定程度的宽频磁光效应增强。通过分析场强分布和仿真结果,证实含多个单层TMDC的复合结构可以同时实现宽频的磁光效应增强和高透过率。展开更多
基金supported by National Natural Science Foundation of China (Grant Nos. 11425418, 11405244, 1127901 and 61521093)Strategic Priority Research Program (B) (Grant No. XDB16)the Open Foundation of the National Key Laboratory of Shock Wave and Detonation Physics
文摘Polarization rotation of a probe pulse by the target is observed with the Faraday rotation method in the interaction of an intense laser pulse with a solid target. The rotation of the polarization plane of the probe pulse may result from a combined action of fused silica and diffused electrons. After the irradiation of the main pulse, the rotation angle changed significantly and lasted ~2 ps. These phenomena may imply a persistent magnetic field inside the target. An analytical model is developed to explain the experimental observation. The model indicates that a strong toroidal magnetic field is induced by an energetic electron beam. Meanwhile, an ionization channel is observed in the shadowgraph and extends at the speed of light after the irradiation of the main beam. The formation of this ionization channel is complex, and a simple explanation is given.
基金Project supported by the National Defense Basic Scientific Research Program of China(No.JCKY2013203B003)
文摘A magnetohydrodynamic （MHD） power generator system involves several subjects such as magnetohydrodynamics, plasma physics, material science, and structure mechanics. Therefore, the performance of the MHD power generator is affected by many factors, among which the load coefficient k is of great importance. This paper reveals the effect of some system parameters on the performance by three-dimensional （3D） numerical simulation for a Faraday type MHD power generator using He/Xe as working plasma. The results show that average electrical conductivity increases first and then decreases with the addition of magnetic field intensity. Electrical conductivity reaches the maximum value of 11.05 S/m, while the applied magnetic field strength is B = 1.75 T. When B 〉 3 T, the ionization rate along the midline well keeps stable, which indicates that the ionization rate and three-body recombination rate （three kinds of particles combining to two kinds of particles） are approximately equal, and the relatively stable plasma structure of the mainstream is preserved. Efficiency of power generation of the Faraday type channel increases with an increment of the load factor. However, enthalpy extraction first increases to a certain value, and then decreases with the load factor. The enthalpy extraction rate reaches the maximum when the load coefficient k equals 0.625, which is the best performance of the power generator channel with the maximum electricity production.
文摘针对单层过渡金属硫化物(transition metal dichalcogenides,TMDC)绝对磁光效应弱,影响了其在磁光装置中的实际应用的问题,提出了3种由单层TMDC和SiC组成的复合结构,通过传输矩阵法分别计算了它们的法拉第旋转(Faraday rotation,FR)角和透过率。研究结果表明:3种复合结构均能实现磁光性能的改善;相对于单层TMDC与SiC基底组成的双层结构,对称复合结构在工作频率处获得了8倍的FR角增强和0.8的透过率;且复合结构还实现了一定程度的宽频磁光效应增强。通过分析场强分布和仿真结果,证实含多个单层TMDC的复合结构可以同时实现宽频的磁光效应增强和高透过率。
