ROLES AND PRODUCTION MECHANISM OF ENERGETIC PARTICLES AT SELF-ORGANIZATION IN REP

本研究的目的是了解京都工业大学STE-2 RFP中含能粒子的产生机理。在第一年，建造了一个X射线探测器，由一个金属靶和一个带有聚酯滤光片的表面势垒二极管组成。同时，为了改善RFP放电，研究了导体壳层的接近程度(b/a，其中b和a分别为等离子体和壳层小半径)对REP等离子体性能的影响。结果表明，放电电阻降低到原来的1/2，壳层性能得到改善(b/a=1.07(SY.scharw.[)1.02)。在接下来的一年里，用STE-2上的X射线探头进行了高能电子研究，壳层非常贴合。得到的主要结果如下：(1)在r/a&gt；0.7的边缘区域，我们观察到能量在400-500 eV的非热电子，远高于40-50 eV的体电子温度。(Ii)高能电子沿磁力线流动，即在中心区受到欧姆电场的加速。(3)高能电子密度随填充压力的增加而减小。高能电子密度与压力的关系是RFP中首次观测到的现象，因此，将结果与快电子产生机制的理论模型进行详细的比较，有助于理解RFP等离子体动力学。对电动势(EMF)探头技术的应用也作了估计。研究发现，在一定的等离子体条件下，可以用该探头估算磁流体动(MHD)发电机项&lt；

The purpose of the present research is to obtain some insights into production mechanism of energetic particles in STE-2 RFP at Kyoto Instute of Technology. During the first year, an X-ray probe, consisting of a metal target and a surface barrier diode with polyester filters, was constructed. And, at the same time, effects of the proximity of conducting shell (b/a, where b and a are the plasma and shell minor radii, respectively) on REP plasma performance were studied for improving the RFP discharges. It was found that discharge resistance decreased by a factor of 2 with an improved shell proimity (b/a=1.07(] SY.scharw.[)1.02). During the following year, energetic electron studies were performed with the X-ray probe in STE-2 with the close fitting shell. The major results obtained are as follows: (i) We have observed non-thermal electrons with energies around 400-500 eV, much higher than the bulk electron temperature of 40-50 eV, in the edge region r/a>0.7. (ii) The energetic electrons flow along the magnetic field line in the sense that they are accelerated by the Ohmic electric field in the central region. (iii) The energetic electron density decreases with an increase in fill pressure. The pressure dependence of the energetic electron density is the first observation in RFP's. Thus, a detailed comparison of the results with theoretical models of production mechanism of fast electrons is beneficial to understanding the RFP plasma dynamics. We have also made an estimate for applying the technique of an electromotive force (EMF) probe which is a combination of a directional probe and a magnetic pickup coil. It has been found that under certain plasma conditions, we can estimate the magnetohydrodynamic (MHD) dynamo term <vxB> with this probe.