AI 中文总结
该研究通过1.5维磁流体动力学模拟，揭示低频脉冲加热的持续时间和日冕磁场强度是调控日冕雨形成、动力学与形态的关键因素。
AI 中文摘要
我们开展数值模拟研究日冕加热和磁场强度如何调控太阳日冕中日冕雨的动力学与形态。日冕雨被广泛认为是热非平衡和热不稳定性的表现形式。过往诸多研究在（准）稳态加热场景下探究凝结过程，但这类加热模型无法完全解释观测到的特性，包括多个团块以及向两个环足点的对称沉降。由低频脉冲加热驱动的凝结过程探究较少，可能产生独特的日冕雨形态和沉降动力学；日冕磁场的作用也尚未明晰。我们沿单根磁 strands 开展1.5维磁流体动力学模拟，模拟包含自洽的日冕加热过程，在此基础上施加单次脉冲加热事件。系统探究两个关键参数：局地加热的持续时间和日冕背景磁场强度。研究发现，单次脉冲加热事件即可触发凝结，前提是注入能量约为稳态加热情形的一个数量级。加热持续时间越长、磁场越弱，凝结越易发生。日冕雨的动力学强烈依赖加热持续时间：当加热持续时间短于辐射冷却时标时，凝结物会向两个环足点沉降。此外，较弱的磁场会增强阿尔文波的非线性，促进凝结物碎片化。这些结果表明，加热持续时间和日冕磁场强度在调控日冕雨形成与动力学中发挥关键作用。
英文摘要
We performed numerical simulations to investigate how coronal heating and magnetic field strength regulate the dynamics and morphology of coronal rain in the solar corona. Coronal rain is widely interpreted as a manifestation of thermal non-equilibrium and thermal instability. Many previous studies have investigated condensation under (quasi-)steady heating scenarios, but such heating models do not fully explain the observed properties, including multiple clumps and symmetric drainage toward both loop footpoints. Condensation driven by low-frequency impulsive heating has been much less explored and may produce distinct coronal rain morphology and drainage dynamics. The role of the coronal magnetic field also remains poorly understood. We conducted 1.5-dimensional magnetohydrodynamic simulations along a single strand with self-consistent coronal heating, upon which a single impulsive heating event was imposed. Two key parameters were systematically explored: the duration of localized heating and the strength of the coronal background magnetic field. We find that condensation can be triggered even by a single impulsive heating event, provided that the injected energy is about an order of magnitude larger than that in the steady heating case. Condensation becomes more likely for longer heating durations and weaker magnetic fields. The dynamics of coronal rain depend strongly on the heating duration. When the heating duration is shorter than the radiative cooling timescale, condensations drain toward both loop footpoints. We also find that weaker magnetic fields enhance the nonlinearity of Alfvén waves, promoting fragmented condensations. These results demonstrate that the heating duration and coronal magnetic field strength play key roles in regulating coronal rain formation and dynamics.
Comments16 pages, 9 figures, Accepted for publication in ApJ
