Research on collapse of double layers and turbulent-heating phenomena

1.电子温度T的时间演化。在从形成到崩溃的双电层（DL）在线性磁阻加热装置中产生的期间，通过使用红宝石激光汤姆逊散射测量。在DL形成之前观察到电子空穴。T.还观察到伴随着电子空穴的衰减，这反过来又导致离子声波的激发，从而形成DL。2。对可能影响DL寿命的参数进行了研究。结果表明，DL的寿命主要取决于两电极间的距离和中性粒子的分压，而与所用材料和壁面尺寸的关系不大.在与实验接近的边界条件下进行了计算机模拟。模拟结果与实验结果吻合较好.基于上述实验和模拟结果，提出了一个理论模型，以理解导致线性湍流加热装置中DL崩溃的物理过程。该模型考虑了在阳极和阴极侧的等离子体密度的不平衡，从DL，这可能是通过DL的“离子输运”所带来的。如此产生的压力不平衡将DL推向阳极。然后，DL消失时，它到达阳极。5.在适当的条件下进行了实验和仿真，验证了所提出的模型，得到了合理的结果.在目前的研究中获得的物理图片有关的DL崩溃的内部结构的变化，而不是传统的机制，由于外部电路，并可能适用于其他DL，如极光。

1. Temporal evolution of electron temperature T. was measured during the period from formation to collapse of double layers (DL) produced in a linear turbulent-heating device, by making use of Ruby laser Thomson scattering. An electron hole was observed berofe the formation of DL. An increase in T. was also observed concomitant with decay of the electron hole,which, in turn, resulted in excitation of ion acoustic waves leading to formation of DL.2. Parameters which may have effect on the life time of DL were examined. It was found that the life time of DL depends strongly on the distance between two electrodes and partial pressure of neutral particles but less on materials used and size of the wall.3. Computer simulation were carried out with boundary conditions close to the experimental ones. Qualitatively good agreement was obtained between experimental and simulation results for the formation process of DLs.4. Based on the experimental and simulation results decribed above, a theortical model was proposed to understand physical process leading to collapse of DL in the linear turbulent=heating device. The model takes into account the inbalance of plasma densities in the anode and cathode sides seen from the DL, which may be brought forth by "the ion transport" through the DL. The pressure inbalance so produced pushes the DL toward the anode. Then the DL vanishes when it reaches the anode.5. Additional experiments and simulations were carried out under the condition appropriate to verify the proposed model, and reasonable results were obtained.6. The physical picture obtained in the present research as to the collapse of DL is related to change in internal structure of DL, as opposed to conventional mechanism due to external cicuit, and may be applied to other DLs such as those in aurora.