纳秒脉冲放电击穿过程中产生的高能电子可以起到引导放电传播和激发活性粒子的作用，研究这些高能电子的产生与演化过程，既可以加深对高气压脉冲放电机理的认识，又可以指导实际应用中放电参数优化。本项目将利用快速电离波放电形式产生稳定、可重复、易诊断的纳秒脉冲击穿过程，采用直接测量与间接发光测量相结合的方法，对宽能量范围高能电子的时空演化行为进行高分辨率的诊断；为了建立高能电子行为与空间电场/电势的关系，将综合采用激光二次谐波产生、发射光谱斯塔克分裂与电容探头等非介入方法，对放电中空间电场/电势的时空演化进行诊断并相互验证；针对纳秒脉冲放电击穿过程中高能电子起源机制问题，本项目将引入脉冲激光与电极、气相成分相互作用机制，独立调控电极表面电子发射通量与空间残余电子密度，研究这两个因素对高能电子产生与演化行为的影响。本项目的研究期望可以推进对高气压脉冲放电机理的认识，指导高活性脉冲等离子体的产生与调控。

The high energy electrons generated during the breakdown process of the nanosecond pulsed discharges can guide the discharge propagation and excite the active species. An investigation of these high energy electrons will deepen the understanding of the physics of pulsed discharges at high pressure and provide a guideline for the parameter-optimization in the plasma application. In this project, the fast ionization wave (FIW) discharge will be used to generate a stable and reproducible nanosecond pulsed breakdown process, which is flexible to be diagnosed. Both direct measurement and indirect radiation measurement will be adopted to obtain the spatial distribution and the temporal evolution of the high energy electrons in a wide energy range with a high resolution. Several non-intrusive methods, i.e. laser second harmonic generation, Stark splitting of optical emission spectroscopy, and capacitive probe, will be used to diagnose the spatial-temporal behavior of the electric field (or the electric potential) in the FIW discharge. Combining both investigations, the relationship between the behavior of the high energy electrons and the evolution of the electric field (or the electric potential) will be investigated. In order to study the origin of high energy electrons, the interaction between the pulsed laser with the electrode and the species in the volume will be introduced and the flux of the electron emission from the electrode surface and the density of residual electrons will be modulated independently, the influence of which on the generation and evolution high energy electrons will be studied. The investigation of this project is expected to improve the understanding of pulsed discharge mechanism at high pressure and provide a guideline for the generation and modulation of highly reactive pulsed plasma.