分析了二极管中爆炸发射产生阴极等离子体的演化特征，在考虑了阴极等离子体朝阳极膨胀运动使二极管阴阳极间距缩短这一效应的同时，还计入了阴极等离子体沿发射表面径向扩展运动对二极管有效发射面积的影响。基于Child-Langmuir定律，利用在一个四脉冲强流电子束源装置上得到的电流、电压等实验数据，假定阴极等离子体轴向膨胀和径向扩展速度近似相等，研究了阴极等离子体的膨胀扩展动力学行为。计算结果表明，阴极等离子体朝阳极的膨胀和沿径向的扩展速度为0.9～2.8 cm/μs。

The evolution characteristics of the cathode plasma in a planar diode with explosive emission were analyzed. Besides the axial expansion which can reduce the effective anodecathode gap, the radial expansion of the cathode plasma which can affect the effective emitting area was also taken into account. According to the ChildLangmuir law and the experimental data of current and voltage with a electron vacuum diode under fourpulse mode, the dynamics of the cathode plasma was investigated, on the assumption that the radial speeds of the cathode plasma was approximately equal to the axial speed. The results show that the radial and axial expansion speeds of the cathode plasma are 0.92.8 cm/μs.