标题： SIP-IFVM：一种具有强磁场的日冕和CME的高效时间精确隐式MHD模型 显示英文标题

标题： SIP-IFVM: An efficient time-accurate implicit MHD model of corona and CME with strong magnetic field

摘要： 日冕物质抛射是空间天气的主要驱动因素之一。 然而，对日冕亚阿尔芬速度区域中日冕物质抛射传播和演化初始阶段的鲁棒且高效的数值模拟仍然缺乏。 基于高度高效的准稳态隐式磁流体动力学日冕模型（Feng等，2021；Wang等，2022a），我们进一步开发了一个高效且时间准确的日冕模型，并利用它来模拟日冕物质抛射的演化和传播。 设计了一种伪时间推进方法，在每个物理时间步引入一个伪时间tau，通过在tau上求解稳态问题来更新解，以提高时间精度。 此外，插入了一个RBSL通量绳，其轴线可以设计成任意形状，以触发日冕物质抛射事件。 我们称其为SIP-IFVM日冕模型，并利用它来模拟CR 2219背景日冕中从太阳表面到20 Rs的日冕物质抛射演化过程。 该模型可以在不到0.5小时（192个CPU核心，1百万个单元）内完成覆盖6小时物理时间的日冕物质抛射模拟，而不会显著损失时间精度。 此外，一个初始磁场人工增加的假设模拟表明，该模型能够有效处理时间依赖的低β问题（β<0.0005）。 另外，一个Orszag-Tang磁流体动力学涡旋流模拟表明，该日冕模型中采用的伪时间推进方法也能够模拟小尺度非稳态流动。 模拟结果表明，该磁流体动力学日冕模型非常高效且数值稳定，有望及时准确地模拟低等离子体β下的太阳日冕中的时变事件。 显示英文摘要

摘要： CMEs are one of the main drivers of space weather. However, robust and efficient numerical modeling of the initial stages of CME propagation and evolution process in the sub-Alfvenic corona is still lacking. Based on the highly efficient quasi-steady-state implicit MHD coronal model (Feng et al. 2021; Wang et al. 2022a), we further develop an efficient and time-accurate coronal model and employ it to simulate the CME's evolution and propagation. A pseudo-time marching method, where a pseudo time, tau, is introduced at each physical time step to update the solution by solving a steady-state problem on tau, is devised to improve the temporal accuracy. Moreover, an RBSL flux rope whose axis can be designed in an arbitrary shape is inserted into the background corona to trigger the CME event. We call it the SIP-IFVM coronal model and utilize it to simulate a CME evolution process from the solar surface to 20 Rs in the background corona of CR 2219. It can finish the CME simulation covering 6 hours of physical time by less than 0.5 hours (192 CPU cores, 1 M cells) without much loss in temporal accuracy. Besides, an ad hoc simulation with initial magnetic fields artificially increased shows that this model can effectively deal with time-dependent low-beta problems (beta<0.0005). Additionally, an Orszag-Tang MHD vortex flow simulation demonstrates that the pseudo-time-marching method adopted in this coronal model is also capable of simulating small-scale unsteady-state flows. The simulation results show that this MHD coronal model is very efficient and numerically stable and is promising to timely and accurately simulate time-varying events in solar corona with low plasma beta.