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离子在静电塞电位或磁镜之间的传递，通过具有非轴对称磁场结构的锚定细胞。通过塞势反射离子的存在是改善串联反射镜中等离子体约束的必要条件。我们使用了两种测量技术来观察反弹离子，一种是使用终端损耗能量分析仪（ELECA）在关闭微波注入到堵塞区域后测量反弹离子出现峰值时的反弹离子，另一种是使用位于堵塞/阻挡电池内镜喉附近的紧凑型电荷交换反弹离子分析仪（CXBIA）测量反弹离子。利用金中性束探针（GNBP）测量了在中心螺线管中激发的Alfven离子-回旋加速器（AIC）波动引起的弹跳离子向损失区的输移，并通过测量末端损失离子的速度分布函数，从速度空间中离子越过损失边界扩散的角度研究了弹跳离子向损失区的输移。我们观察到末端损耗离子的能量分布函数呈现出平缓的驼峰结构，并估计了增强因子。为了控制核心等离子体的径向势分布，我们改变了同轴划分的端板的静电势，并通过实验观察了对势分布的控制效果。假设磁通管的形状与锚细胞镜面喉道处的等势面形状略有不同，计算了被插头电位反弹的离子的轨迹作为径向势线宽度的函数。这种差异增强了反弹离子从反弹区向损失区流动的径向输运。实验和理论证实了核心等离子体的扩散型径向势分布对等离子体密度和弹跳离子密度的增加是有效的。重要的是，从这个角度考虑微波注入对堵塞电位的产生。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