摘要
采用PIC模拟方法,研究了具有谐振腔的多波切伦柯夫振荡器在充入不同密度的氦气下工作的物理过程,分析了等离子体产生物理机制及其对微波输出影响。结果表明,等离子体的产生是由于电子束对氦原子的碰撞电离及其雪崩效应引起的。由于电离产生的正离子有利于束的传输和群聚,当在一定范围内增加氦气密度时,可减小微波起振时间,提高束波能量转换效率,但并不改变微波频率;进一步增大气体密度,微波起振时间增大、效率下降,甚至出现脉冲缩短现象。
The operating process of the multiwave Cerenkov generator with a resonant cavity is simulated when being filled with He gas at various density by PIC method. The generation mechanism of the plasma and its effects on the output microwave are analyzed. The results reveal the plasma is produced owing to the collision ionization of the He gas filled in the tube by the relativistic electron beam and its avalanche ionization effect. Due to the improvement of the beam transporting and bunching by theions tunnel, the starting oscillation time can decrease as well as the energy conversion efficiency be enhanced when increasing the He gas density in a certain range; increasing the He gas density further can result in adverse effects, even induce pulse shortening phenomenon.
出处
《强激光与粒子束》
EI
CAS
CSCD
北大核心
2003年第3期253-256,共4页
High Power Laser and Particle Beams
基金
国家863计划项目资助课题
