| Paper |
Title |
Page |
| TUPPH047 |
Absolute and Convective Instability of Smith-Purcell Free Electron Laser
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431 |
| |
- D. Li, K. Imasaki
ILT, Suita, Osaka
- G. S. Park
SNU, Seoul
- Z. Yang
UESTC, Chengdu, Sichuan
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Smith-Purcell free electron laser can operate on two different modes. The low-energy electron excites the absolute instability and it operates in the manner of a backward-wave oscillator, while the high-energy electron induces the convective instability and it operates like a traveling-wave tube. In this paper, we demonstrate those two instabilities using a two-dimensional particle-in-cell simulation. The simulation model supposes a rectangular grating to be driven by a continuous beam, and the radiation is in the THz regime. The beam bunching and the evolution of the radiation field are observed. The variation of the gain is reported as well.
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| TUPPH049 |
Study on Superradiant Smith-Purcell Radiation
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439 |
| |
- D. Li, K. Imasaki
ILT, Suita, Osaka
- S. Amano, S. Miyamoto, T. Mochizuki
NewSUBARU/SPring-8, Laboratory of Advanced Science and Technology for Industry (LASTI), Hyogo
- G. S. Park, Z. Yang
SNU, Seoul
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A simulation of coherent and superradiant Smith-Purcell radiation is performed in GHz regime using a three-dimensional particle-in-cell code. The simulation model supposes a rectangular grating to be driven by a single electron bunch,a train of periodic bunches and a continuous beam, respectively. The true Smith-Purcell radiation is distinguished from the evanescent wave, which has an angle independent frequency lower than the minimum allowed Smith-Purcell frequency. We also find that the superradiant radiations excited by periodic bunches are emitted at higher harmonics of the bunching frequency and at the corresponding Smith-Purcell angles. The "start current" is determined as well as the distributions of the radiation intensity are presented.
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