非链式HF激光器紫外预电离的数值模拟

Simulation of the ultraviolet pre-ionization in the mixture gas of non-chain HF laser

为了明确紫外预电离对主放电的影响,对光子能量为5 eV和10 eV的紫外光预电离后的电子密度分布进行了研究。首先介绍了紫外预电离过程中发生的主要过程,然后建立了紫外预电离的简单模型,再根据模拟结果分析了上述光子能量的紫外光对气体中电子密度分布的影响。模拟结果表明:总气压为50 kPa、光强为103W/cm2时,上述紫外光的有效作用距离分别为0.15 cm和0.5 cm,即使将光强升至106W/cm2,它们的有效作用距离也仅仅分别增加至0.3 cm和0.8 cm,还无法对主放电产生明显的影响;当总气压为10 kPa时,紫外光的有效作用距离分别达到1.1 cm和2.7 cm,可以对主放电产生明显的影响。这说明:在较低的工作气压下,5 eV和10 eV的紫外光均可以产生明显的预电离效果,较低气压可以获得更大的有效预电离区域和更均匀的预电离电子密度。

The change of the distribution of electron density caused by photo-ionization when hv=5 eV and hv=10 eV was studied to identify the effect of ultraviolet pre-ionization on the main discharge. Firstly, the essential processes in the mixture gas under radiation of ultraviolet was introduced. Then a simple model was established. With the model, the distributions of electron density after the radiation of ultraviolet （hv=5 eV and hv=10 eV） were obtained. The results are as follows： the effective interaction lengths on hv=5 eV and hv=10eV are 0.15 cm and 0.5 cm respectively under the condition of P=50 kPa and I=10^3 W/cm2. When the light intensity is increased to 10^6 W/cm2, the effective interaction lengths increase only to 0.3 cm and 0.8 cm respectively, which can＇t affect the main discharge effectively; when P=10 kPa, the effective interaction lengths are 1.1 cm and 2.7 cm, exerting large effect on the maindischarge. According to the results, the conclusions is as photon energy can affect the discharge effectively when effective if the atmospheric pressure is lower. follows： the ultraviolet with both 5 eV and 10 eV P=10 kPa, and the pre-ionization could be more