Supersonic neutral particle beam for tokamak plasma diagnostics

本研究的主要目的是利用光谱技术，建立一种用于磁约束聚变等离子体边缘区域诊断的超音速氦原子束方法。本文的研究成果概述如下：1。超声速氦原子束在等离子体边缘的原子过程的数值研究：利用一组氦激发态和离子态居群的速率方程，对注入中型托卡马克等离子体（JFT-2M托卡马克）的氦原子束在等离子体边缘的激发和电离过程进行数值研究。结果表明，可以通过测量两对不同的He I线的强度来确定电子密度和温度，并且可以利用激光诱导荧光技术测量在边缘处产生的电场的空间分布。2.等离子体中电离氦原子与氢分子之间的原子碰撞过程：基于碰撞辐射模型，对He^<++>与H_2之间的电荷交换过程进行了数值研究，该过程可能在等离子体的分流中起重要作用。3.提出了一种等离子体速率方程的快速数值计算方法。4.在小型真空室中，利用脉冲喷嘴和一套掠光器构建了超声速氦原子束源。光谱测量显示，这种光束可能适用于环面等离子体。5.利用ECR等离子体源产生了氦亚稳原子束。6.提出了一种考虑磁场影响的激光诱导荧光测量磁约束等离子体中电场分布的方法。

The main objective of this research is to develop a supersonic helium atomic beam method for diagnosis in the edge region in magnetic confined fusion plasmas by use of spectroscopic techniques. The outline of the present research results is as follows :1.Numerical study of atomic processes of the supersonic helium atomic beam in the plasma edges : The excitation and ionization processes of the helium atomic beam injected into a middle size tokamak plasma (the JFT-2M tokamak at JAERI) was numerically studied in the plasma edges by using a set of the rate equations for the populations of the excited and ionic states of helium. It was shown that the electron density and temperature could be determined from intensity measurements of two different pairs of He I lines, and also that spatial distribution of the electric field induced in the edges could be measured by using a laser-induced fluorescence technique. 2.Atomic collision process between ionized helium atom and hydrogen molecule in plasmas : A numerical study on the basis of a collisional-radiative model was performed on a charge-exchange process between He^<++> and H_2, which could play an important role in the divertor plasmas. 3.A fast numerical calculation method of the rate equation for the plasmas was developed. 4.A supersonic helium atomic beam source was constructed by using a pulsed nozzle and a set of skimmer in a small size vacuum chamber. Spectroscopic measurements revealed this beam could be applicability to torus plasmas. 5.A helium metastable atomic beam was produced using a ECR plasma source. 6.A laser-induced fluorescence method for measurement of electric field distribution in magnetically confined plasmas was developed taking account of the effect of the magnetic field.