PLASMA HEAT TRANSPORT ALONG MAGNETIC FIELD UNDER EFFECTS OF POTENTIAL DISTRIBUTION

本研究的目的是研究受控实验条件下等离子体中沿磁力线快速传输能量的物理机制。在各种磁化等离子体中都观察到这种类型的热输运，它与沿开场线的势分布的形成密切相关。实验在GAMMA10串联反射镜的大尺度西端等离子体区进行。筑波。为实验开发的控制旋钮为2.45GHz电子回旋共振加热（ECRH）系统，用于热堤和MESH偏置系统。本研究特别关注的是与热电子的粒子交换有关的对流热输运，热电子通过二次发射大量产生冷电子撞击端板。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速率。更多的B会加深端板的浮势深度，使到达端板的热电子通量减少到一半左右。电子的有效温度随mb的增大而增大。由于离子通量仍然远小于碰撞初生电子的通量，因此大部分的热流是由于电子的对流输运产生的。用热电偶阵列和红外摄像机也观察到板热负荷的减少。这些结果证明了MB在降低等离子体热通量方面的有效性。但是，由于温升的衰减量小于颗粒分析的评估值，因此需要对温度诊断进行进一步的测试。这也可能表明其他热通道比粒子分析仪观察到的热通道更活跃。TD使终板电位加深约10%，而一次电子通量并不总是减小。终板温度总体上呈下降趋势，但在某些等离子体条件下，终板温度会升高。这些观察结果激发了对ECRH下初级电子动力学的详细分析。利用新开发的势模型和热响应函数理论工具，我们发现这些电子在多次加热下转化为Yushmanov粒子，部分被驱动到端板上，增加了热负荷。发现在共振处局部裁剪磁场剖面可以有效地提高TD的效益。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