1989 Fiscal Year Final Research Report Summary
The Inverse Smith-Purcell Effect at Submillimeter Wavelengths
| Project/Area Number |
63460136
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
電子機器工学
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
MIZUNO Koji Research Institute Professor, 電気通信研究所, 教授 (30005326)
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| Co-Investigator(Kenkyū-buntansha) |
BAE Jongsuch Tohoku University Assistant, 電気通信研究所, 助手 (20165525)
ONO Shoichi of Electrical Communication Professor, 電気通信研究所, 教授 (00005232)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Inverse Smith-Purcell effect / Laser-driven linac / Submillimeter wave laser / サブミリ波レ-ザ- |
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| Research Abstract |
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.
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