Direct Measurement of Bounce Ions and Suppression of Radial Transport by Control of Radial Electric Field

本研究的目的是研究通过非轴对称磁场构型的锚室，在静电塞电位或磁镜之间反弹的离子的输运。塞子电势的存在对于改善串联镜中的等离子体约束是必不可少的。我们用两种测量技术对回弹离子进行了观察，即用端损能量分量分析仪(ELECA)测量了在关闭微波注入塞区后出现峰值端损离子时的回弹离子，并用紧凑型电荷交换回弹离子分析仪(CXBIA)测量了回弹离子。回弹离子到损耗区的输运是由中心螺线管中激发的阿尔芬离子回旋(AIC)起伏引起的，并用金中性束探头(GNBP)测量。是在…通过测量端面损耗离子的速度分布函数，从速度空间中穿过损耗边界的离子扩散的角度进行了进一步的研究。用ELECA装置测量了端损离子的能量分布函数，观察到了平缓的驼峰结构，并估算了增强因子。为了控制芯等离子体的径向电势分布，我们改变了同轴分割端板的静电势，并实验观察了控制电势分布的效果。在假定磁通管的形状与锚室镜面喉部的等势面形状略有不同的情况下，计算了塞子电势对反弹离子的轨迹作为径向电势分布宽度的函数。这种差异增强了反弹离子从反弹区流向损耗区的径向输运。我们从实验和理论上证实了核心等离子体的径向势能分布的扩散型对于增加等离子体密度和反弹离子是有效的。重要的是，应从这一角度考虑用于产生塞子电势的微波注入。较少

The purpose of this research is to investigate the transport of ions bouncing between the electrostatic plug potentials or magnetic mirrors passing through the anchor cells having a non-axisymmetric magnetic field configuration. Existence of the bounced ion by the plug potential is essential for improvement of the plasma confinement in the tandem mirror. We observed the bounce ions using two kinds of measurement techniques, that is, we measured the bounce ions as the peaking end-loss ions appeared after switching off the microwave injection into the plug region by use of an end-loss energy component analyzer (ELECA), and we measured the bounce ions by use of a charge exchange bounce ion analyzer of a compact type (CXBIA) located near the inner mirror throat of the plug/barrier cell.The transport of the bounce ions to the loss region, which was caused by the Alfven ion-cyclotron (AIC) fluctuation excited in the central solenoid and measured using a gold neutral beam probe (GNBP), was in … More vestigated from a view point of the ion diffusion across the loss boundary in the velocity space by measurement of the velocity distribution function of the end-loss ion. We observed the gentle hump structure on the energy distribution function of the end-loss ion, which was measured by the ELECA device, and estimated the enhancement factor. In order to control the radial potential profile of the core plasma, we changed the electrostatic potentials of the coaxially divided end plates, and observed experimentally the effect of the control of the potential profile. The trajectories of the bounced ions by the plug potential were calculated as a function of the width of the radial potential profile on the assumption that the shape of the magnetic flux tube was slightly different from the shape of the equi-potential surface at the mirror throats of the anchor cell. The discrepancy enhanced the radial transport for the bounce ions to flow from the bounce region to the loss region.We confirmed experimentally and theoretically that the spread type of radial potential profile of the core plasma was effective for the increase of the density of the plasma and also the bounce ions. It is important that the microwave injection for the creation of the plug potential should be considered from this point of view. Less