论文标题
磁尾等离子体的离子加速器
Ion Acceleration at Magnetotail Plasma Jets
论文作者
论文摘要
我们研究了一系列的地球多尺度（MMS）航天器在（-24、7、4）在地球中心太阳能磁层（GSM）坐标中观察到的一系列地球爆发散装（BBF）。在BBF的前缘，我们观察到复杂的磁场结构。特别是，我们专注于一个呈现小尺度（〜0.5 re）偶极性的链，另一个具有较大尺度（〜3.5 re）偶极性的链条。尽管这两个结构具有不同的尺度，但这两种结构都与能量> 100 keV的上部离子的磁通增加有关。我们研究了离子加速机制及其对质量和电荷状态的依赖。我们表明，与结构尺度小的离子相比，离子散装流量加速了。我们表明，尽管在小规模结构中，陀螺仪的离子与结构的尺度相当，并且在较大尺度结构中的加速度更可能是由于空间有限的电场。
We investigate a series of Earthward bursty bulk flows (BBFs) observed by the Magnetospheric Multiscale (MMS) spacecraft in Earth's magnetotail at (-24, 7, 4) RE in Geocentric Solar Magnetospheric (GSM) coordinates. At the leading edges of the BBFs, we observe complex magnetic field structures. In particular, we focus on one which presents a chain of small scale (~0.5 RE) dipolarizations, and another with a large scale (~3.5 RE) dipolarization. Although the two structures have different scales, both of these structures are associated with flux increases of supra-thermal ions with energies > 100 keV. We investigate the ion acceleration mechanism and its dependence on the mass and charge state. We show that the ions with gyroradii smaller than the scale of the structure are accelerated by the ion bulk flow. We show that whereas in the small scale structure, ions with gyroradii comparable with the scale of the structure undergo resonance acceleration, and the acceleration in the larger scale structure is more likely due to a spatially limited electric field.
