Magnetosheath jets are regions of high dynamic pressure, which can traverse from the bow shock towards the magnetopause. Recent modelling efforts, limited to a single jet and a single set of upstream conditions, have provided the first estimations about how the jet parameters behave as a function of position within the magnetosheath. Here we expand the earlier results by doing the first statistical investigation of the jet dimensions and parameters as a function of their lifetime within the magnetosheath. To verify the simulation behaviour, we first identify jets from Magnetosphere Multiscale (MMS) spacecraft data (6142 in total) and confirm the Vlasiator jet general behaviour using statistics of 924 simulated individual jets. We find that the jets in the simulation are in quantitative agreement with the observations, confirming earlier findings related to jets using Vlasiator. The jet density, dynamic pressure, and magnetic field intensity show a sharp jump at the bow shock, which decreases towards the magnetopause. The jets appear compressive and cooler than the magnetosheath at the bow shock, while during their propagation towards the magnetopause they thermalise. Further, the shape of the jets flatten as they progress through the magnetosheath. They are able to maintain their flow velocity and direction within the magnetosheath flow, and they end up preferentially to the side of the magnetosheath behind the quasi-parallel shock. Finally, we find that Vlasiator jets during low solar wind Alfvén Mach number M_A are shorter in duration, smaller in their extent, and weaker in terms of dynamic pressure and magnetic field intensity as compared to the jets during high M_A.

中文翻译：

---

磁热射流的演化与寿命的关系：与MMS观测值相比的全球混合Vlasov模拟

磁石荒射流是高动压区域，可以从船首冲击向磁层顶横穿。最近的建模工作仅限于单个射流和一组上游条件，已经提供了有关射流参数如何随磁石内位置的变化行为的初步估计。在这里，我们通过对射流的尺寸和参数进行首次统计调查来扩展早期的结果，这些参数是射流尺寸和参数在磁石中的寿命的函数。为了验证模拟行为，我们首先从磁层多尺度（MMS）航天器数据中识别出了喷气机（总计6142），并使用924个模拟喷气机的统计数据确认了Vlasiator喷气机的一般行为。我们发现模拟中的射流与观测值在数量上一致，使用Vlasiator确认与喷气机有关的早期发现。射流密度，动压力和磁场强度在船首冲击时显示出急剧的跳动，并朝着绝经期降低。射流在弓形冲击时显得比磁热强度低且压缩，而在朝向磁绝顶传播期间，它们会热化。此外，射流的形状随着它们穿过磁石破面而变平。它们能够将其流速和方向保持在磁石堆流中，并且优先在准平行冲击之后到达磁石堆的一侧。最后，我们发现低太阳风期间Vlasiator喷流AlfvénMach数 朝向磁致绝经减少。射流在弓形冲击时显得比磁热强度低且压缩，而在朝向磁绝顶传播期间，它们会热化。此外，射流的形状随着它们穿过磁石破面而变平。它们能够将其流速和方向保持在磁石堆流中，并且优先在准平行冲击之后到达磁石堆的一侧。最后，我们发现低太阳风期间Vlasiator喷流AlfvénMach数 朝向磁致绝经减少。射流在弓形冲击时显得比磁热强度低且压缩，而在朝向磁绝顶传播期间，它们会热化。此外，射流的形状随着它们穿过磁石破面而变平。它们能够将其流速和方向保持在磁石堆流中，并且优先在准平行冲击之后到达磁石堆的一侧。最后，我们发现低太阳风时Vlasiator喷流AlfvénMach数 它们能够将其流速和方向保持在磁石堆流中，并且优先在准平行冲击之后到达磁石堆的一侧。最后，我们发现低太阳风期间Vlasiator喷流AlfvénMach数 它们能够将其流速和方向保持在磁石堆流中，并且优先在准平行冲击之后到达磁石堆的一侧。最后，我们发现低太阳风期间Vlasiator喷流AlfvénMach数中号_阿是在动态压力和磁场强度计在其范围中持续时间越短，更小和更弱相比在高射流中号_甲。