http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Sideband Instability in the Compact THz Free-Electron Laser at KAERI
Young Uk Jeong,Byung Cheol Lee,Grigori M. Kazakevitch,Hyuk Jin Cha,Jungho Mun,Pil Dong Ahn,Seong Hee Park 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.I
A frequency offset of the Sideband instability has been observed in a compact waveguide-mode terahertz (THz) free-electron laser (FEL). The spectra of the FEL pulses were measured by using a Fabry-Perot spectrometer having a resolution of 10$^{-4}$ of the central wavelength at 2 $-$ 3 THz range. The shift of the sideband was measured to be 0.5 $-$ 1.2 $\mu$m, depending on the FEL wavelengths from 110 to 165 $\mu$m. An increase in the sideband shift for a longer wavelength could be explained by a change in the wave's group velocity in a plane-parallel waveguide. Mode competition between the sidebands and the primary wave was observed by changing the cavity length of the FEL. We could decrease the number of modes and reduce the linewidth of the spectra by controlling the cavity detuning. We discuss the dependence of the complexity of the sideband instability on the FEL wavelengths and its gain characteristics.
조성오,ByungCheolLee,YoungUkJeong,JaegwonYoo,SeongHeePark 한국물리학회 2002 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.41 No.5
An energy-recovering superconducting linear accelerator is being developed for a high-power infrared free-electron laser (FEL). The design value of the maximum beam current circulating in the superconducting cavities is 50 mA. In such a high-current accelerator, the wakefield excited by the bunches passing through the cavities can induce unstable operation of the accelerator. The effects of the wakefield on the accelerator operation are analyzed for successful lasing of the FEL. The beam quality degradation, the starting current of the beam breakup, and the power loss to the higher-order mode coupler are calculated analytically and numerically. It is found that the accelerator can be operated at the maximum current without having a severe problem caused by the wakefield.