摘要
我们研制了CEBQ程序和ENVLOP程序,模拟稳态相对论电子束在二极管区的产生和加速,以及电子束在阳极通道内的传输过程。CEBQ程序模拟二极管区电子轨道,当阳极电压为1.5MV时,阴极总发射电流为17.9kA,进入阳极通道内的传输电流为4.3kA,阳极入口处D=4cm的束发射度为24.9cm.mrad。ENVLOP程序使用线性近似下的包络方程,描述电子束包络在螺旋管引导磁场作用下的变化,讨论了外加引导磁场对包络的影响。计算结果表明,在合适引导磁场作用下,束包络起伏较小,进入阳极通道的束流(4.3kA)能全部通过。
A 2-D CEBQ code in cylindrical geometry and a ENVLOP code used to simulate the emission and transport of intense relativistic electron beams in LIA are described in this paper. The CEBQ code simulates all electron trajectories in a diode considering effects of space charge and external electric and magnetic field. Poisson equation is solved with the finite element method suitable to complex boundary and clouds in-cell method is used to calculate charge deposition. The problem of β> 1 in numerical simulation is better overcome by using the conservation of canonical angular momentum. Two techniques are employed to improve numerical instability and to steep up the convergence of iteration: subrelaxation iteration for charge density and pervence.
ENVLOP code calculates beam envelope in drift region in a linear approximation.
We present the computed results for 1.5 MeV injector and discuss the effects of guiding magnetic field on beam envelope.
出处
《强激光与粒子束》
EI
CAS
CSCD
1990年第1期59-66,共8页
High Power Laser and Particle Beams
