Foreshock bubbles (FBs) have been observed upstream of solar wind tangential discontinuities (TDs). A hypothesized mechanism is that foreshock ions with gyroradii larger than the TD thickness may move to upstream side of TDs and generate FBs. In this study, we present the very first three‐dimensional global hybrid simulation of an FB driven by a TD. After the TD encounters the ion foreshock, plasma and magnetic field perturbations are generated upstream of the TD. These perturbations are characteristically consistent with the observed TD‐driven FBs, confirming that TDs can form FBs. We further analyze the initial perpendicular temperature increase initiating the FB and compare the temperature structure with that from tracing test‐particles in static TD electric and magnetic fields. The structure can be explained by the perpendicular velocity change of foreshock ions with large gyroradii as they encounter the magnetic field direction change across the TD, which supports the hypothesized mechanism.

中文翻译：

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由IMF切向不连续性驱动的前震泡沫：3D全局混合仿真

在太阳风切向不连续面（TDs）的上游已经观察到前震气泡（FBs）。一种推测的机理是，陀螺半径大于TD厚度的前兆离子可能会移动到TD的上游并生成FB。在这项研究中，我们提出了由TD驱动的FB的第一个三维全局混合仿真。在TD遇到离子前震之后，在TD上游会产生等离子体和磁场扰动。这些扰动与观察到的TD驱动的FB在特性上是一致的，从而证实TD可以形成FB。我们进一步分析了引发FB的初始垂直温度升高，并将温度结构与在静态TD电场和磁场中追踪测试粒子的温度结构进行了比较。