论文部分内容阅读
通过对光致大气击穿过程中的电子连续性方程进行分析,并利用Matlab中的ode45求解器建立了等离子体形成过程中电子密度随时间演化的理论模型。利用该模型计算得到了同一脉宽、不同波长的作用激光击穿大气的阈值,计算得到的结果与文献报道的实验结果吻合得较好,从而验证了这一模型的正确性。通过该模型数值模拟了调Q-Nd:YAG激光击穿大气过程中电子密度的时间演化曲线,并对得到的电子密度演化曲线进行了讨论。结果表明:光致大气击穿过程前期多光子电离占主导地位;中期雪崩电离占主导地位;后期损耗因素占主导地位。
By analyzing the electronic continuity equation in the process of photo-induced atmospheric breakdown and using the ode45 solver in Matlab to establish the theoretical model of the electron density evolution with time in the process of plasma formation. Using this model, we get the laser breakdown threshold of the same pulse width and different wavelength. The calculated results are in good agreement with the experimental results reported in the literature, which verifies the correctness of the model. Through the numerical simulation of the model, the time evolution curve of electron density during the Q-Nd: YAG laser breakdown in the atmosphere was simulated and the electron density evolution curves obtained were discussed. The results show that the multiphoton ionization dominated in the early stage of photoluminescence breakdown, the mid-term avalanche ionization dominates, and the later loss factor dominates.