RT - Journal Article T1 - Dynamics of Electrons in Free Electron Laser with Square Core Waveguides JF - ijop YR - 2016 JO - ijop VO - 10 IS - 2 UR - http://ijop.ir/article-1-246-en.html SP - 69 EP - 79 K1 - free electron laser K1 - wiggler field K1 - square waveguide AB - Due to sensitive and important applications of free-electron laser in industry and medicine, improvement of the power and efficiency of laser has always been emphasized. Therefore, understanding the created field and examining the properties of the field in waveguides with different shapes and studying the sustainability of electrons movement are particularly important. In this study, the behavior of electrons in free-electron laser in the wiggler field by square waveguide with central core is examined which is a new research. Due to the complexity of cross section, the equations governing the field are solved numerically, and magnetostatic fields are calculated and then the changes of Wiggler magnetic field are displayed. Finally, the properties of balanced electron circuits for the first and third harmonics are studied and the strong effect of the third space harmonic on the field is observed in the second magnetic resonance and the obtained results indicate greater volatility of transverse components of velocity. Since the field intensity on the sides and center of the waveguide and the order of electrons motion are important in determining the laser power and efficiency, studying the behavior of electrons in this research indicates that in the empty space between the two walls, Wiggler magnetic field is minimized and leads to the focus of electron beam. Therefore, the closer is the starting point of the movement of electron to the center of waveguide, the better will be the movement order. LA eng UL http://ijop.ir/article-1-246-en.html M3 10.18869/acadpub.ijop.10.2.69 ER -