太阳表面水平运动驱动的磁圈与开放磁场重联的模拟研究

太阳大气的诸多观测事件(如耀斑、喷流等)均被归因于磁重联产生的能量转换. 近年来, 关于太阳风起源, 有研究提出了磁重联使闭合磁圈开放为太阳风供应物质的新模式. 在该模式中, 闭合磁圈被光球超米粒组织对流携带, 向超米粒边界运动, 与位于边界的开放磁场相碰撞进而发生磁重联. 该模式中磁重联的驱动及其效应是本文的研究目标. 磁流体力学(MHD)数值模拟是研究太阳大气磁重联物理过程的重要途径. 本文建立了一个二维MHD数值模型, 结合太阳大气温度和密度的分层分布, 在超米粒组织尺度上模拟了水平流动驱动的闭合磁圈与开放磁场的重联过程. 通过对模拟结果的定量分析, 认为磁重联确实能够将闭合磁圈的物质释放, 进而供应给新的开放磁结构并产生向上流动. 该结果为进一步模拟研究太阳风初始外流奠定了基础.

Study of Magnetic Reconnection Between Closed Loops and Open Magnetic Field Driven by Horizontal Flows on Solar Surface

Numerous observational events in the solar atmosphere (e.g., solar flares and jets) are attributed to be the energy conversion due to magnetic reconnection. Magnetic reconnection is also involved in a new scenario of solar wind origin to play a crucial role in opening the closed loop and releasing its mass into the open funnel. In the scenario, closed loop are moved towards the supergranular boundary by the supergranular advection, colliding with open magnetic funnel there and triggerring magnetic reconnection between each other. This work aims at studying the occurrence and effect of magnetic reconnection in the scenario in details. Magnetohydrodynamic (MHD) numerical simulation is an important approach to investigate the magnetic reconnection process in the solar atmosphere. A 2D MHD numerical model in supergranular scale is established, which starts from the solar atmosphere with stratified layers of temperature and density. Based on quantitative analysis of the simulation result, the conclusion that the mass flow in the open funnel can be supplied from the closed loop aside through magnetic reconnection as driven by supergranular advection is suggested. Our results lay the foundation for future modeling of solar wind origin.