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A method of studying a non-equilibrium x-ray laser plasma is developed by extending the existing one-dimensional similarity equations to the case of two-dimensional plasma study in the directions perpendicular to the slab and along a focal line.With this method the characteristics of pre-plasma are optimized for transient neon-like Cr x-ray laser.It is found that when the duration and the intensity of 1.053 μm pre-pulse are 1.2 ns and 6.5 TW/cm2 respectively with a delay time of 1.5 ns,the temperature and the temperature discrepancy each approach a proper state,which will provide a uniform distribution of properly ionized neon-like Cr ions before the arrival of pumping pulse.  相似文献   
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为了获取强激光驱动产生的X射线光源焦斑尺寸和空间分辨率,设计了刃边及双网格方法,其中刃边厚度为0.2μm,双网格分别为400目铜网格和394lp/cm的镍网,利用X射线CCD作为探测元件。Ti宝石激光在能量1J、脉宽40fs、频率10 Hz、激光功率密度约为4.4×1018 W/cm2的条件下,重复频率加载圆盘Cu靶。在中国工程物理研究院25TW激光装置上首次获得了X射线的焦斑及网格图像,并推算了该装置的X射线焦斑尺寸为43μm,而网格空间分辨力为34μm。结果表明该刃边及双网格方法适合强激光驱动产生的X射线焦斑尺寸测定。  相似文献   
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程涛  李英骏  孟立民  李希波 《中国物理 B》2011,20(2):24206-024206
Based on the two-dimensional model,this paper compares the hydrodynamics of slab x-ray laser plasma produced by different nonuniform line focused irradiations.It finds that the average intensity and the duration of laser pulse and the overall shape of the intensity distribution in the focal line have different influences on the plasma.Calculations show that the evolution of temperature variation is more sensitive to the pulse duration and the electron density variation is more sensitive to the pulse intensity.Pulses with duration of 200 ps to 500 ps and with intensity of 0.2 TW/cm 2 to 1.0 TW/cm 2 are proved acceptable in slab x-ray lasers.  相似文献   
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利用激光离焦的方法优化超强激光驱动的质子加速   总被引:1,自引:0,他引:1       下载免费PDF全文
在中国科学院物理研究所"极光Ⅱ 号"飞秒激光装置上,对激光与薄膜靶相互作用产生的靶后质子束特性进行了实验研究.结果发现,在主脉冲前存在较强的飞秒预脉冲的情况下,通过适当地对激光束散焦,可以使质子束的转换效率提高3 个数量级,并同时改善质子束的准直性.分析表明,激光散焦的方法可以有效地抑制预脉冲的流体力学效应对质子加速的负面影响,从而提高质子的转换效率.此外,粒子模拟还发现,散焦量增大时可以产生更多的中低能超热电子,这也有利于建立高质量的质子加速电场. 关键词: 超短脉冲激光与等离子体相互作用 质子加速 转换效率  相似文献   
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孟立民  滕爱萍  李英骏  程涛  张杰 《物理学报》2009,58(8):5436-5442
从自相似方法出发,建立了简化的二维X射线激光等离子体流体动力学模型. 利用该模型研究了平板靶X射线激光的二维流体力学行为. 研究表明,当激光作用结束后,经过一段时间的演化电子密度和温度沿线聚焦方向逐渐达到平衡,该结果对X射线激光的优化设计具有重要意义. 关键词: X射线激光 二维流体力学计算 自相似方法  相似文献   
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An experiment on a transient nickel-like Mo x-ray laser in the extreme light Ⅲ (XL Ⅲ) laser facility is analyzed, based on the two-dimensional hydrodynamic evolutions of a plasma under a non-uniform incident laser. Influences of the pulse duration and intensity on plasma scale length, electron density, temperature, as well as their distributions are investigated, based on which the pre-pulse character and delay time are determined according to the parameters of laser line focus on XLⅢ. It is found that the optimal intensity of the pre-pulse is 1.0 TW/cm^2 with a duration of 500ps; a well modified pre-plasma can be obtained after 1.6ns under low quality line focus in the lab.  相似文献   
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程涛  黄文忠  孟立民  李英骏  赵静  张杰 《光子学报》2008,37(11):2288-2291
从理论上论证了利用平板靶X射线激光两个输出端光强对称的特性来测量X射线多层膜镜反射率的测量方法.针对实验布局中等离子体对X射线激光吸收可能造成测量误差的情况,以保证测量结果千分之一的精确度为基准,从理论上计算获得该方法对不同波长X射线激光的实验布局要求.并依此要求对制得的Mo/Si、Mo/Mg镜的反射率进行了实验测量.  相似文献   
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Mode coupling in nonlinear Kelvin--Helmholtz instability   总被引:1,自引:0,他引:1       下载免费PDF全文
This paper investigates the interaction of a small number of modes in the two-fluid Kelvin-Helmholtz instability at the nonlinear regime by using a two-dimensional hydrodynamic code. This interaction is found to be relatively long range in wave-number space and also it acts in both directions, i.e. short wavelengths affect long wavelengths and vice versa. There is no simple equivalent transformation from a band of similar modes to one mode representing their effective amplitude. Three distinct stages of interaction have been identified.  相似文献   
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