Particle Flow and Dynamic Response of Potential Formation at the Plug Region of a Tandem Mirror

本研究的目的是通过研究与电子加热相关的串联镜塞区颗粒流的变化来了解塞势形成的机制。本文研究了电子回旋共振加热（ECRH）过程中从塞区到端板的电势结构的动态变化。主要结果如下：(1)塞式ECRH成电位是一个动态过程，密度分布与电位变化密切相关。而且，齿轮的插头电位与端板电位一致。这意味着端板电位对从真空容器测量的插头电位有很大的影响。(2)我们提出了一个等效电路模型，其中包括从插头/阻挡区到端板的电流分布和电位结构。插头ECRH的作用是在这个电路中产生电动势。根据从每个区域到真空容器的有效电阻的值，这个电动势分为插头电位和负端板电位。(3)本电路中的电流流经端板前面的护套区域。从载流护套的角度对端板电势进行了分析，证实了电势模型的有效性。(4)理论研究与上述调查同时进行。我们已经成功地开发了一个潜在的模型，包括温度各向异性作为ECRH和修正玻尔兹曼关系的结果。这个模型正确地预测了潜在创造物的动态行为。指出了库仑碰撞对轴向位分布的连续性的重要性。

The objective of this research is understanding of the mechanism of the plug potential formation through investigation of the change of particle flow at the plug region of a tandem mirror associated with electron heating. In this year, dynamic variation of the potential structure from the plug region to the end plate during electron cyclotron resonance heating (ECRH) has been studied. Main results are as follows.(1) It has been found that potential formation by the plug ECRH is a dynamic process in which the density distribution and the change of the potential is closely linked. Moreover, the plug potential gears with the end plate potential. This means that the end plate potential has a large influence on the plug potential as measured from the vacuum vessel.(2) We have presented a model of an equivalent circuit that includes the current distribution from the plug/barrier region to the end plate and potential structure. The role of the plug ECRH is generation of the electromotive force in this circuit. This electromotive force is divided into the plug potential and the negative end plate potential according to the values of the effective resistance from each region to the vacuum vessel.(3) The current in this circuit flows through the sheath region on front of the end plate. The analysis of the end plate potential from the viewpoint of a current carrying sheath has confirmed the validity of our potential model.(4) Theoretical studies have been carried out along with the above investigations. We have succeeded to develop a potential model that includes the temperature anisotropy as a result of ECRH and the modified Boltzmann relation. This model correctly predicts the dynamic behavior of the potential creation. The importance of the Coulomb collisions for continuity of the axial potential profile near the plug region has been pointed out.