Achievement of Ultimate Performances of Laser Spectroscopic Methods for Measurements of Electric Fields in Plasmas and Gases

这项研究是为了实现测量等离子体和气体中电场的激光光谱方法的最终性能，即：(I)便于测量不仅由He组成的辉光放电等离子体中的电场，以及(Ii)探索在大气中测量电场的可能性。这些措施有很大的需求。取得的结果如下：1.首次对Ar原子的斯塔克效应进行了光谱研究，得到了非常有用的信息。这包括澄清对电场敏感的里德堡能级，以及电场和斯塔克移动量之间的关系(下文第11项中的第二条)。已经证明，电场的方向可以通过使用激光的偏振来确定(下面第11项中的第三条)。明确了两步激光诱导荧光的适用范围，特别是对He、Ar3等原子的激光诱导荧光。为了测量雷暴云下的电场和大气中的势垒放电电场，对研制中的关键技术--Ar原子的三光子激发进行了测试。结果产生了容易填充的级别，从而使未来的发展成为可能。

This research has been carried out to achieve ultimate performances of laser spectroscopic methods for measurements of electric fields in plasmas and gases ; namely (i) to facilitate measurements of electric fields in glow discharge plasmas constituting not only He but other atoms such as Ar, and (ii) to pursue possibility of electric field measurements in atmosphere. There have been great demands for these measurements.Obtained results are as follows.1. The first spectroscopic study of the Stark effect for Ar atoms has been conducted, and yielded very useful information. This includes the clarification of Rydberg levels which are sensitive to electric fields, and of the relationship between the electric fields and the amounts of Stark shifts (the second article in the item 11 below).2. It has been shown that the direction of an electric field can be decided by the use of the polarization of a laser (the third article in the item 11 below).3. Applicable ranges of the two-step laser induced fluorescence have been clarified, especially for atoms such as He and Ar.4. In order to measure electric fields under thunderclouds and in barrier discharges in atmosphere, the three photon excitation of Ar atoms, which is the key technology for the development, has been tested. The results have yielded the levels which are easily populated, thus enabled future developments.