太阳耀斑/CME电流片中湍流磁重联的数值实验

The current sheet (CS) and associated magnetic reconnection during the Flare/CME events are hot issues of solar physics. The non-potential magnetic energy stored in the large-scale coronal structure has been transported to local region of the reconnecting CS continuously. Magnetic energy has been dissipated and transformed to thermal and kinetic energy of plasma and other forms of energy by lots of small-scale physical processes inside the CS, such as plasmoid instability, turbulence and slow-mode shock wave. The solar eruption involves large spatial and temporal span, from large-scale of corona magnetic structure to several hundred meters of ion inertia length. Magnetic reconnection serve as a bridge connecting macroscopic and microscopic scales, physical processes inside the CS are dynamic, multiscale and highly nonlinear. In this study, we start with flux-rope model for solar eruptions; adopt un-uniform calculation mesh, auto mesh refinement and domain decomposition method as the technologies, which overcome in part the multiscale character of eruptive events to simulate the magnetic reconnection process embedded in the large-scale magnetic structure. Concretely, our attention will be concentrated on several solar radius long line CS in two dimensions, includes its geometries, structure evolution, turbulence reconnection inside, small-scale physical processes, magnetic energy's transportation and dissipation.

耀斑/日冕物质抛射（CME）事件中电流片，及其内部的磁重联过程是太阳物理领域中的热点问题。在爆发事件中存贮在日冕大尺度磁结构中的非势磁能被持续地转移到局部重联电流片区域。磁能被多种电流片内部的小尺度物理过程，比如等离子体团不稳定性、湍流和慢模激波等，耗散掉并转化为等离子体热能、动能以及其它形式的能量。整个爆发过程的时空跨度大，从日冕大尺度磁结构到上百米左右的日冕大气中离子惯性长度；而磁重联在整个过程中起着承上启下的作用，其涉及的物理过程是动态的、多尺度的和高度非线性的。本项目从磁通量绳模型出发，采用不均匀计算网格，网格自适应和区域分解等针对多尺度物理过程的数值技术，先后开展两个二维球坐标下的数值实验，来研究镶嵌在大尺度磁结构中的重联电流片。我们将重点考察电流片的几何结构、随时间的演化规律、内部湍流磁重联过程、内部的小尺度结构、磁能的逐级转移和耗散。