激光致空气电离的离子引出研究

原子法激光分离同位素(AVLIS)离子引出特性的研究是十分重要的.实验发现，采用YAG激光器四倍频脉冲激光与真空室内平行极板间的空气相互作用，可以电离空气，产生等离子体.在平行板电极施加高压，可以使空气等离子体中的离子引出，最终被负极板收集.通过分析所采集收集的离子引出信号，得到了离子引出的规律.采用数值计算的方法对氮分子的离子引出信号进行模拟，通过与实验得到的离子引出信号进行比较，发现数值计算结果与实验结果能很好地吻合，从而证明可以用数值计算的方法进行简单的离子引出信号分析.进一步分析得到了不同条件下的空气中离子引出信号规律，总结出提高离子效率的方法.并讨论了离子引出时间与极板间电压、等离子体宽度、等离子体密度的关系.

Study of ion extraction from laser-induced air plasma

Study on ion extraction characteristics is of great significance in atomic vapor laser isotope(separation)(AVLIS).Plasma is instantly produced by means of the interaction between the YAG laser pulse quadruple output and air in the interspace of parallel-plate electrodes in the vacuum chamber.Ion is(extracted) from the plasma by hundreds of volts applied over the parallel-plate electrodes and collected by the negative plate.Ion extraction characteristics are concluded by analyzing the signals recorded by oscilloscope.The comparison of the ion extraction signals is made between the numerical simulation result and(experimental) data,and it is found that the two methods agree well with each other.As a result,the(numerical) calculation can be used as a method to analyze ion extraction characteristics.Then further(discussion) is developed under different conditions with numerical simulation method on the purpose of(obtaining) the best way to enhance ion extraction efficiency.The relation between ion extraction time and three controllable parameters-applied voltage,plasma width and plasma initial density,is discussed.