Title: Flare energetics, CME launch and heliospheric propagation for the May 2024 events, as derived from ensemble MHD modelling Show Chinese title

Title: 2024年5月事件的耀斑能量学、日冕物质抛射发射和日球传播，来源于集合MHD建模

Abstract: Many questions must be answered before understanding the relationship between the emerging magnetic flux through the solar surface and the extreme geoeffective events. The main ingredients for getting X-ray class flares and large interplanetary Coronal Mass Ejections (CMEs) are the build-up of electric current in the corona, the existence of magnetic free energy, magnetic energy/helicity ratio, twist, and magnetic stress in active regions (ARs). The upper limit of solar energy in the space research era, as well as the potential for experiencing superflares and extreme solar events, can be predicted using MHD simulations of CMEs. To address this problem, we consider the recent events of May 2024 and use three MHD models: 1) OHM ("Observationally driven High order scheme Magnetohydrodynamic code") for investigating the magnetic evolutions at a synthetic dipole structure. 2) TMF (time-dependent magneto-friction) for setting up an initial non-potential magnetic field in the active region. A zero-beta MHD model for tracing the magnetic evolution of active regions. 3) EUHFORIA (''European heliospheric forecasting information asset'') for interplanetary CME propagations. For the eruptive flares with CMEs, magnetic solar energy is computed along with data-constrained MHD simulations for the May 2024 events. We show the consistency between the data-initiated realistic simulation of the May 2024 big event and energy scalings from an idealised simulation of a bipolar eruption using OHM. The estimated free magnetic energy did not surpass $5.2 \times 10^{32}\;$erg. Good arrival time predictions ($<3$ hours) are achieved with the EUHFORIA simulation with the cone model. We note the interest in coupling all the chains of codes from the Sun to the Earth and developing different approaches to test the results. Show Chinese abstract

Abstract: 在理解通过太阳表面出现的磁通量与极端地磁效应事件之间的关系之前，必须回答许多问题。 获得X射线级耀斑和大尺度日球层日冕物质抛射（CMEs）的主要因素是日冕中电流的积累、磁自由能的存在、磁能/螺旋度比、扭转以及活动区（ARs）中的磁应力。 在空间研究时代，太阳能量的上限以及经历超级耀斑和极端太阳事件的可能性可以通过CME的MHD模拟进行预测。 为了解决这个问题，我们考虑了2024年5月的近期事件，并使用了三种MHD模型：1）OHM（“观测驱动的高阶方案磁流体动力学代码”）用于研究合成偶极结构中的磁演化。 2）TMF（时间依赖磁摩擦）用于在活动区建立初始非势磁场。 一个零β MHD模型用于追踪活动区的磁演化。 3）EUHFORIA（“欧洲日球层预测信息资产”）用于行星际CME传播。 对于伴有CME的爆发耀斑，磁太阳能量与2024年5月事件的数据约束MHD模拟一起计算。 我们展示了2024年大型事件的数据启动真实模拟与使用OHM的理想化双极爆发模拟的能量标度之间的一致性。 估计的自由磁能未超过$5.2 \times 10^{32}\;$erg。 使用锥形模型的EUHFORIA模拟实现了良好的到达时间预测（$<3$小时）。 我们注意到将从太阳到地球的所有代码链耦合起来的兴趣，并开发不同的方法来测试结果。