空间电荷效应对阴极微凸起热不稳定性的影响

Influence of space charge effect on thermal instability of cathode microprotrusion

由于金属微凸起爆炸电子发射的预发射电流密度一般都超过108A/cm2,因此必须考虑其空间电荷效应的影响。基于金属微凸起爆炸电子发射起始过程模型,通过理论分析和数值模拟,给出了考虑预发射电流空间电荷效应的微凸起爆炸发射延迟时间随二极管平均电场的变化关系。与不考虑预发射电流空间电荷效应的结果进行对比表明,预发射电流的空间电荷效应可以显著增加金属微凸起的爆炸发射延迟时间。

Due to the high density of the prebreakdown current of explosive electron emission, the space charge effect should be considered in the simulation of the initial thermal instability of explosive electron emission. Based on the metallic microprtrusion model of explosive electron emission, a model dealing with the space charge effect is presented. The simulation results show that the space charge effect could greatly lengthen the delay time of explosive electron emission. According to the simulation, the thermal instability process is strongly affected by the space charge effect of prebreakdown current. The space charge effect of prebreakdown current should not be neglected in the analysis of microprotrusion model of explosive electron emission.