球形闪电形成机理及其在核聚变领域应用可行性的研究

Magnetic confinement thermonuclear fusion is seen as the most promising way to develop fusion energy, but magnetic confinement is the most difficult aspect to achieve fusion. Lawrence Livermore Laboratory in the United States dedicated Sustained Spheromak Physics Experiment (SSPX) for simulating the natural way to achieve fusion without the applied magnetic field or with weak magnetic field constraint. As typical plasma structures in nature, there are ball lightning can be achieved in the lab. Through multivariable coupling calculation to the structure of ball lightning and plasma, simulation operation to large eddy simulation can be carried for the flow field, and the ball lightning forming conditions can be derived. By experiments conducted measurements, tangential velocity and axial velocity component in paraxial, transition and the near wall region cyclone, the distribution of the fluid flow field of the arc plasma can be obtained with the two radial velocity component of the axial section swirl distribution, and analysis of how to improve the cyclone intensity. For the Spheromak by coaxial helicity injection to SSPX, analysis the distribution of the ratio of the current and the magnetic field distribution and safety factor. By the ideal MHD simulations to Taylor relaxation edge distribution in the injector, the analysis can be made for constraint regional safety factor profile. And the analysis can be made for how to make use of the plasma distribution of ball lightning, by the current distribution significantly different from Taylor states or other effects to improve magnetic shearing.

磁约束热核聚变被看成是开发聚变能源中最有希望的途径，但磁约束又是实现聚变的难点。美国Lawrence Livermore实验室采用SSPX维持型球马克，模拟自然界方式在无外加磁场或者加弱磁场约束情况下实现聚变。在自然界中典型的稳定等离子结构中有球形闪电可以在实验室实现。我们将对球形闪电等离子位形结构采用多变量耦合运算，对流场进行了大涡模拟，得到球形闪电实现条件。并通过实验对近轴，过渡区旋流切向速度分量和轴向速度分量进行测量，得到电弧等离子体流体流场的分布、轴向截面上旋流的两个速度分量径向分布，并分析如何提高旋流强度。同时分析用同轴螺旋性注入维持的球马克在电流与磁场之比的分布和安全因子分布。对注入器中的Taylor弛缘分布进行理想MHD模拟，得出约束区域的安全因子分布，分析如何借鉴球形闪电的等离子体分布、通过明显不同于Taylor态的电流分布或其它效应如等离子体流来改善磁剪切。

磁约束热核聚变被看成是开发聚变能源中最有希望的途径，但磁约束又是实现聚变的难点。而旋转马克和球马克模拟自然界方式在无外加磁场或者加弱磁场约束情况下实现聚变，MHD平衡主要依靠自感应电流。在自然界中典型的稳定等离子结构中有球形闪电。通过对球形闪电等离子位形结构采用多变量耦合运算，对流场进行了大涡模拟，得到了球形闪电实现条件。并通过实验验证在实验室获得了球形闪电。这次实验的意义在于，证实了在放电结束之后球形等离子体能持续存在，并且首次发现从一个球形等离子体分离出了两个球形等离子，而其中一个完全独立于电极而存在。同时还通过粒子算法对雷电放电过程进行了模拟，通过变量耦合计算得到了整个过程中电子浓度、正离子浓度、电子热能的空间分布，分析了空间电荷作用下电场的畸变。另外还分析了自约束球形等离子的稳定性，通过分析得出自约束球形等离子体内的平衡压力分布量小于球外的环境压力，压力梯度指向球外，同时等离子体球在自平衡时在磁轴和边界上的安全因子小于1，从理论上证实了球形等离子体自约束的平衡态基本上是关于局域模扰动稳定的。参考Rotamak和球马克，并根据本次实验产生球形等离子体的方法和球形等离子体的稳定特性提出了一种新的紧凑型聚变反应装置，克服了传统托卡马克装置约束效率不高、体积大和不能稳态运行的缺点。