The trajectory of electron , the electronic energy , emittance and the bunch length in the accelerating process are presented . primary properties parameters are obtained on different positions 雖然第一加速段之前的漂移距離較長,但縮短該漂移段距離的模擬表明對提高束流性能的作用不大。
To make pic ( particl - in - cell ) simulations . to set up models of guns and magnetic field and simulate them in the vacuum and plasma , respectively . we found that plasma held back part of space charge effects and improved trajectory of electrons . but beam would oscillate and became instable as accretion of plasma density . by simulating again and again , we draw a conclusion magic could n ' t work when plasma density was more by far than beam electron density . at last a four - stage depressed collector was simulated 建立電子槍和聚焦系統(tǒng)模擬模型,分別在真空和填充等離子體條件下進行模擬。發(fā)現(xiàn)填充等離子體能補償部分空間電荷效應,改善電子束包絡軌跡,提高電子的流通率,但是隨著等離子體密度的增大,束電子會出現(xiàn)振蕩不穩(wěn)定性,遺憾的是通過反復多次模擬發(fā)現(xiàn)本文所用粒子模擬的代表性軟件magic無法用于模擬等離子體密度遠高于束電子密度的情況。