The geo-effectiveness of coronal mass ejections (CMEs) is a critical area of study in space weather, particularly in the lesser-explored domain of CME–CME interactions and their geomagnetic consequences. This study leverages the Space Weather Adaptive SimulaTion framework to perform 3D MHD simulation of a range of CME–CME interaction scenarios within realistic solar wind conditions. The focus is on the dynamics of the initial magnetic flux, speed, density, and tilt of CMEs, and their individual and combined impacts on the disturbance storm time (Dst) index. Additionally, the kinematic, magnetic, and structural impacts on the leading CME, as well as the mixing of both CMEs, are analyzed. Time-series in situ studies are conducted through virtual spacecraft positioned along three different longitudes at 1 au. Our findings reveal that CME–CME interactions are nonuniform along different longitudes, due to the inhomogeneous ambient solar wind conditions. A significant increase in the momentum and kinetic energy of the leading CME is observed due to collisions with the trailing CME, along with the formation of reverse shocks in cases of strong interaction. These reverse shocks lead to complex wave patterns inside CME2, which can prolong the storm recovery phase. Furthermore, we observe that the minimum Dst value decreases with an increase in the initial density, tilt, and speed of the trailing CME.

中文翻译：

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使用 SWASTi 框架的磁流体动力学模拟研究日冕物质喷射-日冕物质喷射相互作用的演变和地效


日冕物质抛射 （CME） 的地效是空间天气的一个关键研究领域，尤其是在 CME-CME 相互作用及其地磁后果的鲜为人知的领域。本研究利用空间天气自适应模拟框架，在真实的太阳风条件下对一系列 CME-CME 相互作用场景进行 3D MHD 模拟。重点是 CME 的初始磁通量、速度、密度和倾斜的动力学，以及它们对扰动风暴时间 （Dst） 指数的单独和综合影响。此外，还分析了对领先 CME 的运动学、磁性和结构影响，以及两种 CME 的混合。时间序列原位研究是通过位于 1 AU 的三个不同经度上的虚拟航天器进行的。我们的研究结果表明，由于环境太阳风条件不均匀，CME-CME 相互作用沿不同经度是不均匀的。由于与尾随 CME 发生碰撞，观察到领先 CME 的动量和动能显着增加，并且在强相互作用的情况下会形成反向冲击。这些反向冲击导致 CME2 内部出现复杂的波型，从而延长风暴恢复阶段。此外，我们观察到最小 Dst 值随着尾随 CME 的初始密度、倾斜和速度的增加而降低。