共查询到14条相似文献,搜索用时 62 毫秒
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高次谐波的产生(HHG)是一种获取高频相干光的重要技术。其产生机理为:原子(离子)的外层电子在强激光的作用下产生电离,电离后的电子在激光场的作用下运动,在一定条件下,电子可以回到母离子所在的位置,与离子复合并发出一个高能量的光子,其能量等于电子返回时的动能加上电离能。为了得到很高的光子能量,必须采用高强度的驱动激光。如果激光强度接近10^17W/cm^2或更高时,由磁场产生的洛仑子力将阻止电子回到母离子,因而大大降低高次谐波的产生效率。 相似文献
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带电粒子沟道辐射作为γ-激光的可能性 总被引:2,自引:0,他引:2
将沟道辐射与自由电子激光进行类比,讨论了电子轴沟道辐射作为γ激光的可能性.引入等效磁场描述电子的运动行为,并通过等效磁场与辐射场相互作用描述了电子的纵向运动,导出了系统的摆方程和能量增益,得到了与自由电子激光完全类似的结果. 相似文献
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分析了自生磁场对相对论谐波辐射的影响,得出结论,自生磁场对强激光在欠稠密等离子 产生的相对论相干波辐射有重要作用,自生磁场激发偶次谐波辐射,并对奇次谐波辐射产生影响,对二次,三次谐波作了详细分析,发现,自生磁场激发二次谐波辐射,而对三次谐波辐射有削弱作用,并且它还使谐波的失相时间延长。 相似文献
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An alternative approach to analyze the nonrelativistic quantum dynamics of a rigid and extended charged particle taking into account the radiation reaction is discussed with detail. Interpretation of the field operators as annihilation and creation ones, theory of perturbations and renormalization are not used. The analysis is carried out in the Heisenberg picture with the electromagnetic field expanded in a complete orthogonal basis set of functions which allows the electromagnetic field to satisfy arbitrary boundary conditions. The corresponding coefficients are the field operators which satisfy the usual commutation relations. A nonlinear equation of motion for the charged particle is obtained. A careful consideration of the quantum effects allows the derivation of a linear equation of motion which is free of both runaway solutions and preacceleration, even for a point charge. Also, the electromagnetic mass, which is defined as the coefficient of the acceleration operator, vanishes for a point particle. However, this does not mean that the results are free of ambiguities which are exhibited and discussed. 相似文献
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The luminescence response of the leaves of higher plants exposed to laser radiation with different energy and time parameters has been investigated at a wavelength of 685 nm. The plants were irradiated by laser radiation at 1060, 632, and 530 nm. Radiation at = 632 nm was used as the control. It is shown that radiation at = 1060 nm suppresses photosynthesis, whereas that at = 530 nm stimulates it. 相似文献
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Per Olof Fröman 《Annals of Physics》2007,322(9):2145-2167
The paper deals with a class of integrals, the integrands of which contain the square of a solution of a second-order linear, ordinary differential equation. Such integrals often arise in quantum mechanics as normalization integrals or expectation values. A generalized, unified procedure for rewriting such an integral, associated with a differential equation of the Sturm-Liouville type with unspecified boundary conditions, as a parameter derivative is presented. The formula thus obtained can be used for the evaluation of various integrals of physical interest. As an application we present a simplified derivation of a formula given by de Alfaro and Regge, in which the quantal normalization integral is expressed in terms of the Jost function. Other applications to integrals involving special functions and to integrals associated with the one-dimensional Schrödinger equation are also presented. Furthermore, it is explained why an approximate formula for expectation values is much more accurate than one can expect from the usual, crude derivation of it, and why certain attempts to improve that derivation have failed. 相似文献
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黑体辐射是近代物理史上一只会下金蛋的鹅,是近代物理的摇篮。黑体辐射研究的意义还在于这是唯一一个涉及c,k,h三个普适常数的物理情景。黑体辐射谱抗测量误差的特性带来了辐射标准和绝对温度参照,谱分布公式对模型的不敏感则使得黑体辐射成为独特的物理研究母题。黑体辐射谱分布公式,普朗克多角度推导过,德拜推导过,艾伦菲斯特推导过,劳厄推导过,洛伦兹和庞加莱深入讨论过,泡利推导过,玻色推导过,爱因斯坦在20多年的时间里多角度推导过且产出最为丰硕,近代还有从相对论角度的推导,每一个角度的推导都带来了物理学的新内容,这包括量子力学、固体量子论、受激辐射、量子统计、相对论统计,等等。认真回顾黑体辐射研究的历史细节,考察其中的思想概念演化,不啻于体验一次教科书式的学(做)物理之旅,比如也可以尝试给出能量局域分立化的简单新证明。 相似文献