Computer Simulations of Radiation Generation From Relativis-tic Electron Beams

PI建议使用改进的相对论电磁粒子代码以及在他们之前的NSF资助下开发的现有代码（ECS-8219105）来解决有关从相对论电子束产生相干辐射的关键问题。模拟研究将在微波范围内进行，包括自由电子激光器、电子回旋脉泽和切伦科夫脉泽。本研究将探讨交流和直流空间电荷场对各种大电流自由电子器件的增益、谐振条件和非线性效率的影响；各种自由电子器件的横向模式竞争利用背景等离子体对光束直流空间电荷和电流进行中和的有效性，以及利用相对论电子束与等离子体填充波导相互作用构建相干辐射源的可行性；以及平面介质波导中的切伦科夫脉泽和使用绕轴大电子轨道的高谐波回旋管的效率。

The PI's propose to use improved relativistic electromagnetic particle codes as well as existing codes developed under their previous NSF grant (ECS-8219105) to address crucial issues concerning the generation of coherent radiation from relativistic electron beams. The simulation studies will be carried out in the microwave range and will include the free-electron laser, electron cyclotron maser, and Cherenkov maser. The research will investigate: the effects of ac and dc space charge fields on the gain, resonant condition and nonlinear efficiency of various high current free electron devices; the transverse mode competition in various free electron devices; the effectiveness of using a background plasma for beam dc space charge and current neutralization and the feasibility of using the interaction between relativistic electron beams and plasma filled waveguides to build coherent radiation sources; and the efficiency of a Cherenkov maser in a planar dielectric waveguide and a high-harmonic gyrotron using axis-encircling large electron orbits.