Population Inversion in High Density Recombining Plasmas

高密度重组等离子体中的粒子数反转

基本信息

批准号：
60460224
负责人：
ODA Toshiatsu
金额：
$ 4.35万
依托单位：
HIROSHIMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-60460224/
关键词：
Population Inversion Recombing Plasmas Laser Oscillation Ionized Helium z-pinch Gun 占有密度

项目摘要

The main purpose of this project is to investigate the dominant processes leading to the population inversion in recombining plasmas for development of the short-wave laser. We have made both theoretical and experimental studies on the recombining plasmas produced by interaction of high density plasmas with neutral gases. The main results obtained in this project are as follows :1. A simulation using a CR model has shown that laser oscillation between the hydrogen levels n=2 and 3 can be genarated in a recombining hydrogen plasma interacting with a dense helium gas as a cooling medium.2. The optimum condition of initial electron density and temperature. decay time and plasma shape for VUV coherent laser oscillation has been presented for <He^+> recombining plasma. The continuous coherent laser of He <II> 164nm line which corresponds to the transition n=3->2 in <He^+> is possible if a sufficiently thin sheet plasma flow in a steady state with the electron density of <10^(15)> - <10^(16)> <cm^(-3)> is cooled down to 0.2eV with decay time of <10^(-7)> [ <10^(-8)> s. 3. A helium recombining plasma of <n_e> = <10^(16)> <cm^(-3)> and <T_e> =4eV has been produced by a Z-pinch gun plasma injected into a helium neutral gas of 0.26 Torr. Strong population inversion was found between <He^+> n=4 and 5 levels. The one-pass gain was estimated for a 3cm plasma column. and found to exceed a threshold for the laser oscillation if a pair of mirrors with reflectivity of 99% and 99.8% was installed.4. The present experimental results suggest that the electron temperature of the recombining plasma will be cooled down to less than leV by introduction of much more dense hydrogen gas through a fast acting valve into the Z-pinch device. Then. strong inversion between <He^+> n=2 and 3 levels will be possible.

该项目的主要目的是研究导致重组等离子体中粒子数反转的主要过程，以开发短波激光器。我们对高密度等离子体与中性气体相互作用产生的复合等离子体进行了理论和实验研究。本课题取得的主要成果如下： 1．使用CR模型进行的模拟表明，在与作为冷却介质的致密氦气相互作用的重组氢等离子体中可以产生氢能级n=2和3之间的激光振荡。 2．初始电子密度和温度的最佳条件。已经针对 <He^+> 复合等离子体提出了 VUV 相干激光振荡的衰减时间和等离子体形状。如果足够薄的片状等离子体流处于稳定状态且电子密度<10^( 15)> - <10^(16)> <cm^(-3)> 冷却至 0.2eV，衰减时间为 <10^(-7)> [ <10^(-8)> s。 3. 将 Z 箍缩枪等离子体注入 0.26 的氦中性气体中，产生 <n_e> = <10^(16)> <cm^(-3)> 和 <T_e> =4eV 的氦重组等离子体。托尔。在 <He^+> n=4 和 5 水平之间发现了强烈的粒子数反转。单程增益是针对 3 厘米等离子柱进行估计的。发现如果安装一对反射率分别为99%和99.8%的镜子，激光振荡会超过阈值。 4．目前的实验结果表明，通过快速作用阀将密度大得多的氢气引入到 Z 箍缩装置中，重组等离子体的电子温度将被冷却至低于 1V。然后。 <He^+> n=2 和 3 级之间的强反转是可能的。