论文标题
冷云与热风的相互作用：云生长和破坏的制度以及磁场的影响
Interaction of a cold cloud with a hot wind: the regimes of cloud growth and destruction and the impact of magnetic fields
论文作者
论文摘要
多相星系风，通过星系光环的冷气积聚以及水母星系剥离的气体是冷气候和热气态相之间相互作用的例子。此类系统中有两个重要的制度。由于开尔文·赫尔姆·霍尔茨（Kelvin-Helmholtz）的不稳定性，火风摧毁了足够小的冷云，从而将云碎成小块，最终混合在热风中。相反，从大云中剥离的冷气将与热风混合到中等温度，然后变成热不稳定并冷却，从而导致热气净积聚到冷尾。使用Magneto-Hydrodannical Code AREPO，我们对云粉碎模拟和测试分析标准进行了生长和破坏制度之间过渡的测试标准，以阐明文献中当前的辩论。我们发现热风冷却时间设定了过渡半径，而不是混合阶段的冷却时间。磁场会改变风云相互作用。风磁场的悬垂增强了云上游的场，流体不稳定性被湍流的磁性风抑制，超出了具有均匀磁场的风的风。我们进一步预测，水母星系将订购与尾部对齐的磁场。我们最终讨论了如何使用理想化的模拟的结果来为宇宙学（磁性）流体动力学模拟中的亚网格模型提供输入，这些模拟无法解决圆周循环中冷气云的详细小规模结构。
Multiphase galaxy winds, the accretion of cold gas through galaxy haloes, and gas stripping from jellyfish galaxies are examples of interactions between cold and hot gaseous phases. There are two important regimes in such systems. A sufficiently small cold cloud is destroyed by the hot wind as a result of Kelvin-Helmholtz instabilities, which shatter the cloud into small pieces that eventually mix and dissolve in the hot wind. On the contrary, stripped cold gas from a large cloud mixes with the hot wind to intermediate temperatures, and then becomes thermally unstable and cools, causing a net accretion of hot gas to the cold tail. Using the magneto-hydrodynamical code AREPO, we perform cloud crushing simulations and test analytical criteria for the transition between the growth and destruction regimes to clarify a current debate in the literature. We find that the hot-wind cooling time sets the transition radius and not the cooling time of the mixed phase. Magnetic fields modify the wind-cloud interaction. Draping of wind magnetic field enhances the field upstream of the cloud and fluid instabilities are suppressed by a turbulently magnetised wind beyond what is seen for a wind with a uniform magnetic field. We furthermore predict jellyfish galaxies to have ordered magnetic fields aligned with their tails. We finally discuss how the results of idealised simulations can be used to provide input to subgrid models in cosmological (magneto-)hydrodynamical simulations, which cannot resolve the detailed small-scale structure of cold gas clouds in the circum-galactic medium.
