【作者】 杨小松；

【导师】 刘三秋；

【作者基本信息】 南昌大学 ， 材料物理与化学， 2012， 博士

【摘要】 能源问题已成为制约当今社会发展的重要因素。多束高功率激光驱动的惯性约束核聚变是研究解决这一全球性问题的可行方案之一。在多束激光辐照靶面的实验中重复观察到磁重联的快速发生,但现有模型并未给出令人信服的解释。对激光等离子体中的快速磁重联研究,不仅可为推动激光聚变的实现提供理论支持,而且能推广应用到其他等离子体环境中的磁重联及其相关现象,如磁约束装置。另一方面,利用等离子体物理的研究方法,在牛顿引力近似下的引力等离子体研究已经得到了很多重要的结果,如土星环、星系旋臂结构、大尺度Pancake结构的形成和Titius-Bode定则等；在更为精确地后牛顿近似下,考虑粒子流引起的磁性引力场的作用,将得到引力系统更为全面的规律,为引力场理论的完善和发展提供新的思路。本论文首先基于激光等离子体中磁重联的研究进展,将有质动力驱动的磁重联模型拓展应用到离子处于多电荷态的激光等离子体中,并首次用来解释两束激光与铝靶相互作用的快速磁重联实验。研究表明有质动力驱动的快速磁重联模型所得到的重联时标和等离子体喷流速度与实验观测结果一致,这意味着两束激光与铝靶作用的快速磁重联可以由有质动力驱动磁重联模型很好的解释。其次,在后牛顿和弱场近似下,基于描述波-波、波-粒的非线性相互作用得到自生磁性引力包络场非线性控制方程,我们研究了自引力系统的磁调制不稳定性。研究结果表明,自引力系统是调制不稳定的；而且,纵扰动不稳定性导致的特征尺度大于横扰动的特征尺度,这种不稳定将导致甚大尺度上初始均匀的背景物质处于各向异性状态；同时由于不稳定性导致扰动物质密度、电性引力场以及自生低频磁性引力场的各向异性坍塌；最终将形成旋转的盘状天体。最后,我们对本论文的主要工作进行了简要总结,并对后续工作进行了展望。更多还原

【Abstract】 With the social development, energy problem have become the bottleneck restriction factor for the social progress. The inertial confined fusion driven by multi-beam of high power lasers is a feasible way to solve the global problem. The fast magnetic reconnection phenomenon has been repeatedly observed in laser plasma experiments with multi-beam lasers irradiated target, but the convincing explanations have not been given by the existing models. Identify the mechanism that driven the fast magnetic reconnection can provide theoretical support to promote the realization of the laser fusion, and also can be extended to the studies of the magnetic reconnection and related phenomena in other plasma environment, such as magnetic confinement devices. On the other hand, based on the analogy between the plasma and gravitating media, and the research experience of linear and nonlinear plasma physics, it has obtained a lot of important results in the frame the Newton’s gravity approximation, such as the rings of Saturn, the clustering structures, the large-scale pancake structures and the law of Titius-Bode, and so on. Under the more accurately Post-Newton approximation, the gravito-magnetic field effect will be considered, and more actual law for the gravity system will be obtained. It may make perfect to the gravitational field theory and provide some new ideas for development of the gravitational field theory.Firstly, we extend the model of fast magnetic reconnection to include plasmas with multiple-charged ions that we then apply to two-beam laser-solid interactions. Properties of the magnetic reconnection process, such as the reconnection time scale and jet velocity, are obtained with classical values of the Spitzer resistivity. The results are consistent with experimental measurements, which indicate that the phenomenon of fast magnetic reconnection can be well described by our model for magnetic reconnection driven by ponderomotive force.Secondly, under the approximation of Post-Newtonian as well as the weak-field, the modulational instabilities for longitudinal and transverse gravito-electromagnetic perturbations are investigated on the basis of the self-generated gravitomagnetic field equations in a self-gravitating system. The results indicate that the self-gravitating system is modulational instability. The characteristic scale of longitudinal perturbation is much larger than the transverse one. The anisotropic accumulation of matter and the generation of a gravitomagnetic field are in favor of the formation of a rotationally pancake-like structure.Finally, the summary of this paper have been given briefly, and prospects of the future work have been proposed.更多还原