为理解磁绝缘线振荡器(MILO)实验中频频出现的模式竞争问题,利用3维全电磁粒子模拟程序对C波段MILO的实验模型进行研究,探索各种非对称激励机制对产生微波模式的影响,结果显示:阴极电子随机发射、电压的慢上升前沿、较低的电压等因素都可导致非对称高阶模式的产生,并使输出微波功率大大降低。模拟计算得出MILO中存在频率为3.6 GHz左右的基模和频率分别为3.7,4.1,4.6 GHz左右的3种高阶模式,与Karat计算结果基本一致。

The C-band magnetically insulated transmission line oscillator(MILO) has been simulated by the three dimensional PIC code in order to study the influence of non-symmetry excitation mechanisms on its output modes. It is found that the non-symmetry excitation mechanisms,such as random emitting of cathode electron and the long rise time and low magnitude of input voltage,could produce higher order modes and reduce output power. The 3.6 GHz fundamental mode of the designed MILO,and three higher order eigenmodes of 3.7,4.1,4.6 GHz were found in the simulation.The results are similar to those obtained by Karat.