紧凑型L波段磁绝缘线振荡器的粒子模拟

采取减小阴极杆半径和长度、阴阳极间隙、叶片的长度和厚度及慢波结构周期的办法构造了一种紧凑型磁绝缘线性振荡器（MILO），并用2.5维全电磁PIC方法对这一器件进行了粒子模拟研究。该装置主频为1.9GHz，饱和后平均输出功率达5.4GW，束波转换效率达12％。紧凑型MILO结构能避免电击穿，电子束发射的对称性较易控制。

Analysis of the influence of the magnetic field profiles on the high-power gyrotron''''s magnetic injection gun

In order to improve the performance of the magnetic injection gun(MIG),the beam has the mezzo velocity ratio between 1.5 and 2.0 and trans-velocity spread lower than 5%.Three kinds of the magnetic field:the sin function magnetic field,the conic function one and the tanh function one, are discussed. Each kind of field distribution was changed and the simulation shows that:if sin or conic function field is used ,the beam performance can be improved by changing the flat region length,i.e.,moving the turning point near the end of the control anode ,then the velocity ratio will be maximum;if the tanh one is adopted ,and the field angle is in the range 9°to 70°,when the field angle increases,the velocity ratio increases as well as the trans-velocity spread remains stable.