共查询到20条相似文献,搜索用时 15 毫秒
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《中国物理快报》2017,(1)
Thomson scattering imaging(TSI) is proposed and experimentally demonstrated to observe the fine structure of the laser wake field. By Thomson scattering a co-propagating laser pulse, we obtain clear images indicating that the wake field is like an acaleph swimming behind the pump laser. The wavelength of the wake field observed at different electron densities agrees well with the theory. Since no mathematics transformation is involved, TSI could be potentially used as an online monitor for future 'tabletop' plasma accelerators. 相似文献
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K. K. Gadeev A. V. Denkevits A. A. Ivanov V. A. Nikiforov V. V. Shapkin 《等离子体物理论文集》1984,24(3):143-149
The paper presents the results of the experimental investigation of the beam plasma discharge spatial structure in crossed fields induced by adding a high ionization potential gas to the discharge. Direct experimental evidence of the polarization mechanism of the radial current in a device with this type of discharge has been obtained. 相似文献
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利用包括实散射的闭合轨道理论和分区自洽的迭代算法,计算了标度能量为ε =- 0 .0 3,标度电场F =0 .0 1时的平行电磁场中n≈ 4 0 ,m =0的Li原子闭合轨道以及光吸收谱.介绍了谱的标度特性 ,它对理解量子与经典之间的对应关系具有非常重要的意义.并与同样情况下的氢原子谱作了比较 .验证了离子实对光吸收过程的重要作用. By employing the semiclassical closed-orbit theory including core-scattering and region-splitting consistent iterative method, we calculate the closed-orbits and the recurrence spectra of n≈40, m=0 Li Rydbergatom in parallel electric and magnetic fields at scaled energy ε=-0.03. The constant scaled electric field is =0.01 . The novel spectral structures are compared with those of hydrogen obtaines by standard closed orbit theory. The effect of the core-scattering has been discussed. 相似文献
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介绍了一种掺Nd2O3纳米颗粒的溶胶体系,对其光散射特性和消光系数进行了理论分析和数值模拟.结果表明,当溶胶体系中Nd原子的浓度为1.386×1020cm-3Nd2O3纳米颗粒的半径为5nm、相对折射率小于1.25时,对1064nm波长激光的散射损耗不超过0.002 cm-1.因此,掺Nd2O3纳米颗粒的溶胶体系可能是一种理想的激光介质. 相似文献
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激光目标探测装置的回波特性及目标识别技术研究 总被引:5,自引:6,他引:5
提出了一种基于目标面元三维坐标和脉冲飞行时间的激光目标探测装置的回波脉冲功率描述方法,理论推导了激光目标探测装置的探测目标和气旋粒子的面元散射光功率和回波总功率的计算公式,并给出了回波信号的仿真计算脉冲波形.同时根据目标和气旋粒子回波脉冲的幅度 脉宽信息,提出了识别目标与干扰脉冲波形的新方法. 相似文献
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高浓度掺钕钇铝石榴石(Nd∶YAG)晶体的光谱与激光特性 总被引:1,自引:0,他引:1
测量了高掺杂浓度Nd∶YAG晶体的吸收光谱和荧光寿命。晶体的主吸收峰在 80 8nm处 ,Nd掺杂的摩尔分数为 0 0 30的Nd∶YAG晶体的吸收系数高达 2 0 7cm-1,荧光寿命为 15 0 μs,存在浓度猝灭。进行了钛宝石激光抽运高掺杂浓度Nd∶YAG和Nd∶YVO4 晶体的激光性能对比实验 ,所用Nd∶YAG晶体摩尔分数为 0 0 2 0和 0 0 2 5 ,激光斜率效率分别为 2 9 7%和 32 % ;Nd∶YVO4 晶体摩尔分数为 0 0 30 ,激光斜率效率为 34 7% ,表明了高浓度Nd∶YAG晶体在激光性能上与高浓度的Nd∶YVO4 晶体相当 相似文献
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Jochen Brüning Vladimir Geyler Konstantin Pankrashkin 《Communications in Mathematical Physics》2007,269(1):87-105
We provide an exhaustive spectral analysis of the two-dimensional periodic square graph lattice with a magnetic field. We show that the spectrum consists of the Dirichlet eigenvalues of the edges and of the preimage of the spectrum of a certain discrete operator under the discriminant (Lyapunov function) of a suitable Kronig-Penney Hamiltonian. In particular, between any two Dirichlet eigenvalues the spectrum is a Cantor set for an irrational flux, and is absolutely continuous and has a band structure for a rational flux. The Dirichlet eigenvalues can be isolated or embedded, subject to the choice of parameters. Conditions for both possibilities are given. We show that generically there are infinitely many gaps in the spectrum, and the Bethe-Sommerfeld conjecture fails in this case.The work was supported by the Deutsche Forschungsgemeinschaft, the Sonderforschungsbereich “Raum, Zeit, Materie” (SFB 647), and the International Bureau of BMBF at the German Aerospace Center (IB DLR, cooperation Germany–New Zealand NZL 05/001) 相似文献
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We develop the semi-closed orbit theory from two degrees of freedom to three non-separable degrees of freedom and put forward a new model potential for the Li Rydberg atom, which reduces the study of the system to an effective one-particle problem. Using this model potential and the closed orbit theory for three degrees of freedom, we calculate the recurrence spectra of Li Rydberg atom in perpendicular electric and magnetic fields. The closed orbits in the corresponding classical system have also been obtained. The Fourier transformed spectra of Li atom have allowed direct comparison between the resonance peaks and the scaled action values of closed orbits, whereas the nonhydrogenic resonance can be explained in terms of the new orbits created by the core scattering. Our result is in good agreement with the quantum spectra, which suggests that our calculation is correct. 相似文献
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WANG De-Hua LIN Sheng-Lu WANG Mei-Shan YANG Chuan-Lu 《理论物理通讯》2006,46(3):545-552
We develop the semi-closed orbit theory from two degrees of freedom to three non-separable degrees of freedom and put forward a new model potential for the Li Rydberg atom, which reduces the study of the system to an effective one-particle problem. Using this model potential and the closed orbit theory for three degrees of freedom, we caiculate the recurrence spectra of Li Rydberg atom in perpendicular electric and magnetic fields. The closed orbits in the corresponding classicai system have also been obtained. The Fourier transformed spectra of Li atom have ailowed direct comparison between the resonance peaks and the scaied action values of closed orbits, whereas the nonhydrogenic resonance can be explained in terms of the new orbits created by the core scattering. Our result is in good agreement with the quantum spectra, which suggests that our calculation is correct. 相似文献
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DU Meng-Li 《理论物理通讯》2003,39(6):705-708
We derive a formula for double-pulse spectra from closed-orbit theory. We then calculate the double-pulsephotodetachment spectra of H- in the presence of parallel electric and magnetic fields. We analyze the spectra in termsof closed-orbits of the system. We suggest a method for the measurement of a phase associated with each closed-orbit. 相似文献
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Using the matrix diagonalization method, we have studied two kinds of level anticrosing of Rydberg cesium atom in parallel electric and magnetic fields. Our numerical results reveal that in the vicinity position of level crossing between different parity states in a magnetic field, the energy levels and other behaviors of the states are quite sensitive to the electric field. We tabulate some features which may be as a guide in experimental verification. 相似文献
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Experimental observations on a wave packet in a positive column of helium discharge with magnetic fields are reported. The wave packet is a kind of ionization wave and is created by applying voltage pulses to a mesh grid. When an axial non-uniform magnetic field is applied to a positive column, the plasma parameters change inhomogeneously near the magnetic coil. So various characteristics (amplitude, frequency, wavelength and so on) of the wave packet are changed at the both sides of the coil. The wavelength of the wave making up the wave packet varies continuously with a magnetic field. On the contrary, its amplitude and frequency vary remarkable near the magnetic coil, as a strong magnetic field is applied. 相似文献
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用非直观偏振参数显微成像,即采用在传统显微光路中插入模式化装置,通过拟合过滤后对所得数据反演成像,通过对金属纳米颗粒在近场空间散射光谱分析,来解决空间散射现象。用非直观偏振参数显微成像与传统直观成像做对比,并通过时域有限差分法建模仿真,来描述近场直观与非直观散射光谱的差异,对比结果发现,非直观偏振参数显微反演成像的分辨率比直观成像更高,不但能够清晰的探测到纳米颗粒的形状和电场分布,而且比直观成像获得更广泛的空间散射光谱。 相似文献