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The Inverse Smith-Purcell Effect at Submillimeter Wavelengths

亚毫米波长下的逆史密斯-珀塞尔效应

基本信息

批准号：
63460136
负责人：
MIZUNO Koji
金额：
$ 4.29万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

This research project has been planned to experimentally verify the theoretical predictions on the inverse Smith-Purcell (ISP) effect which is a candidate for laser- driven linacs with an accelerating gradient of several GeV/m.In the ISP effect, an electron beam interacts synchronously with an evanescent wave on the grating when the velocity of electron is the same as the phase velocity of the wave. The interaction-strength and -space also vary with an incident laser power, the wavelength, an order of space harmonics of the evanescent wave, and an initial velocity of electron. In order to investigate these experimentally, we have measured energy spread of electron resulted from the interaction with the 1st or the 2nd space harmonics. These waves have been induced by two different driving submillimeter wave lasers with the wavelengths of 496mum and 185mum. Experimental results have been compared with computer simulated one performed before the experiment. In summary, we have obtained the following verifications for the theory.(1) The velocity matching condition described above has been confirmed experimentally for the 1st and the 2nd space harmonics of the evanescent wave.(2) The amplitude of the evanescent wave falls off exponentially with the distance from the grating surface, and its decay constant agrees with the theoretically predicted one within our experimental errors. For example, in the laser-wavelength of 185mum, this value is 1/(18<plus-minus>8mum) as compared with the theoretical one of 1/(16.6mum) for the 1st space harmoni(3) The energy spreads of electron depended on the incident laser power agree with theoretically predicted one within correction factor of 2.

该研究项目计划通过实验验证逆史密斯-珀塞尔（ISP）效应的理论预测，该效应是加速梯度为数GeV/m的激光驱动直线加速器的候选者。在ISP效应中，当电子速度与波的相速度相同时，电子束与光栅上的倏逝波同步相互作用。相互作用强度和空间也随着入射激光功率、波长、倏逝波的空间谐波的阶数以及电子的初始速度而变化。为了通过实验研究这些，我们测量了由于与第一或第二空间谐波相互作用而产生的电子能量扩散。这些波是由波长为 496mum 和 185mum 的两种不同驱动的亚毫米波激光器引起的。实验结果与实验前进行的计算机模拟结果进行了比较。综上所述，我们得到了以下理论验证：(1)倏逝波的一阶和二阶空间谐波的速度匹配条件已通过实验得到证实。(2)倏逝波的振幅随着距光栅表面的距离呈指数衰减，其衰减常数在实验误差范围内与理论预测一致。例如，在激光波长为 185mum 时，该值为 1/(18±8mum)，而第一空间谐波的理论值为 1/(16.6mum) (3)。取决于入射激光功率的电子能量分布与校正因子 2 内的理论预测值一致。