Production of super-Alfvenic plasma flow and elucidation of magneto-plasma fluid dynamics with structural change

在这项研究中，我们进行了各种实验，目的如下。(1)宽范围离子马赫数M_i和阿尔芬马赫数M_A参数的实现。(2)为了建立超阿尔芬等离子体流中马赫数的控制方法和进行各种实验研究，本文对超阿尔芬等离子体流中的磁等离子体动力学进行了研究，包括：（1）在高β等离子体流中验证推广的Bernouilli方程;（2）建立快速流动等离子体中绝热指数的实验估算方法;（3）阐明与磁场结构变化有关的超阿尔芬等离子体流中磁等离子体动力学。对磁等离子体动态电弧发动机（MPDA）进行了改进，在改进后的MPDA喷口处加装小磁线圈形成磁喷嘴，利用多次反射式可见光激光干涉仪测量了MPDA出口附近的电子密度，测量了磁喷嘴区域的电子密度，并测量了不同磁结构下的等离子体流动动力学，特别是利用离子加热和磁喷嘴的结合。实验成功地产生了超Alfvenic等离子体流，并在较宽的M_i和M_A参数范围内实现了等离子体流动。目前还没有实验测量绝热指数的研究。从磁喷管中快速流动等离子体的特性出发，建立了绝热指数的估算方法。从而建立了快速流动等离子体的产生和控制方法，并在较宽的M_i和M_A参数范围内，从实验上阐明了快速流动等离子体的动力学。在这项研究中，我们获得了许多与各种等离子体物理和应用研究相关的重要知识。

In this research we have carried out various experiments for the following purposes.(1) Realization of wide range of ion Mach number M_i and Alfven Mach number M_A parameters.(2) Verification of the extended Bernouilli's equation in a high-beta plasma flow,(3) Establishment of the experimental evaluation method of an adiabatic exponent in a fast-flowing plasma,(4) Elucidation of magneto-plasma dynamics in a super-Alfvenic flow associated with structural change of magnetic field.In order to establish control method of the Mach numbers and to perform various experimental researches in a super-Alfvenic plasma flow, a magneto-plasma-dynamic arcjet (MPDA) was modified and small magnetic coil was attached to form magnetic nozzle at the muzzle of the improved MPDA.A multiple-reflection type visible light laser interferometer was equipped for electron density measurement near the MPDA exit, and the electron density in the magnetic nozzle region was measured.We have also measured plasma flow dynamics in various magnetic configurations, especially utilizing the combination between ion heating and magnetic nozzle. A super-Alfvenic plasma flow was successfully generated and plasma flows were realized in a wide range of M_i, and M_A parameters.In order to analyze the plasma flow dynamics, it is necessary to evaluate the adiabatic exponent of ions experimentally. There was no research to measure the adiabatic exponent experimentally until now. We have established the evaluation method of an adiabatic exponent from the behavior of fast-flowing plasmas in magnetic nozzle. It was also able to clarify temporal evolution of the adiabatic exponent.As a result, we have established the generation and control method of fast-flowing plasma, and clarified experimentally dynamics of fast-flowing plasmas in a wide range of M_i and M_A parameters. In this research, we have obtained a lot of important knowledge related to various plasma physics and applied researches.