PLASMA HEAT TRANSPORT ALONG MAGNETIC FIELD UNDER EFFECTS OF POTENTIAL DISTRIBUTION

本研究计划的目的是在受控的实验条件下，探讨等离子体中能量沿沿着磁力线快速传输的物理机制。在各种磁化等离子体中都观察到这种热输运，它与沿着开场线电势分布的形成密切相关。实验是在筑波大学中国实验室的伦敦西区大尺度等离子体区，在伽马10串列反射镜上进行的。为实验开发的控制旋钮为2.45GHz电子回旋共振加热（ECRH）系统和网格偏置系统。在这项研究中，特别关注的是与热电子的粒子交换相关的对流热传输，热电子与通过二次发射大量产生的冷电子撞击端板。TD增强了磁镜反射，MB增强了冷电子的静电反射，从而降低了两类电子的交换率。M 关于我们 B加深了端板的浮置电势深度，使得到达端板的暖电子通量减少到大约一半。电子的有效温度随MB的增加而增加。大部分的热通量归因于对流电子传输，因为离子通量保持比撞击初级电子的通量小得多。用热电偶阵列和红外照相机也观察到了板的热负荷的减少。这些结果证明了MB在降低等离子体中的热通量方面的有效性。但是，由于温度上升的减量小于从颗粒分析中评估的减量，因此需要对温度诊断进行进一步测试。TD使终板电位加深约10%，而初级电子通量并不总是减少。终板温度总体上呈下降趋势，但在某些条件下有所上升。这些观测结果促使我们对ECRH下初级电子的动力学进行了详细的分析，利用新开发的势模型和加热响应函数的理论工具，我们发现这些电子在多次加热下转化为Yushmanov粒子，并部分被驱动到终板，增加了热负荷。局部剪裁的磁场分布在谐振被发现是有效的，在增加TD的好处。少

The purpose of this research program is to investigate physical mechanisms of rapid energy transort along magnetic field lines in plasmas under controlled experimental conditions. This type of heat transport is observed in a variety of magnetized plasmas, and it is closely connected with the formation of potential distribution along the open field lines. The experiments are made in the large-scale west end plasma region in the GAMMA10 tandem mirror in PRC,Univ.of Tsukuba. The control knobs, developed for the experiment, are 2.45GHz Electron Cyclotron Resonance Heating (ECRH) system for THERMAL DIKE and MESH BIAS system. Special concern in this study lies in convective heat transport associated with particle exchange of hot electrons that hit end plates with cold electrons abundantly produced via secondary emissions. TD enhances magnetic mirror reflections and MB increases electrostatic reflection of the cold electrons so as to reduce the exchange rate of the two classes of electrons. M … More B deepens the depth of floating potential of the endplates, so that the warm electron flux reaching the endplates decreases to about a half. The effective temperature of the electrons increases with MB.Most of the heat flux is attributed to the convective electron transport because the ion flux remains much smaller than the flux of impinging primary electrons. The reduction of the heat load to the plate is also observed with a thermo-couple arry and with infra-red camera. These results demonstrate the effectiveness of MB in reducing the heat flux in plasmas. But, since the decrement of the temperature-rise is smaller than that evaluated from the particle analyzes, further tests are required on the temperature diagnostics. It may also indicate that other heat channels are active than those watched with the particle analyzers.TD deepens the endplate potential by about 10% while the primary electron flux does not always decrease. The endplate temperature tends to decrease as a whole, though under some plasma conditions it increases, These observations motivated detailed analyzes of dynamics of primary electrons under ECRH.Using newly developed theoretical tools of a potential model and heating response function, we found that these electrons are transformed to Yushmanov particles subject to multiple heating and partially driven to the endplates, increasing heat-load. Local tailoring of the magnetic field profile at the resonance is found to be effective in increasing the benefit of TD. Less