Sheared magnetic field structure in Jupiter's dusk magnetosphere: Implications for return currents
Sheared magnetic field structure in Jupiter's dusk magnetosphere: Implications for return currents
复制标题
木星黄昏磁层中的剪切磁场结构：对返回电流的影响
DOI：
10.1029/2001ja000251
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发表时间：
2002
影响因子：
--
通讯作者：
R. Walker
中科院分区：
文献类型：
--
作者：
M. Kivelson;K. Khurana;R. Walker
[1] 木星磁层黄昏扇区中 100 RJ 附近的磁场配置随距赤道电流片的距离而变化。子午面扭曲的变化与赤道附近滞后同转但可能导致高纬度地区同转的气流一致。尽管部分场扰动可能是由磁层顶电流产生的，但我们认为，观测到的剪切场结构需要场对准电流流向磁层顶内部木星电离层，但超过 100 RJ。该电流必须包括系统的返回电流的一部分，其强制向外移动的磁层等离子体的部分共转，并且还可以由区域1类型的边界层电流馈送。我们估计进入极光电离层的总电流为±6MA，并且该电流将流入主极光椭圆形极地方向的狭窄纬度带（<2°）。索引术语：5737 行星学：流体行星：磁层 (2756)； 2756 磁层物理学：行星磁层（5443、5737、6030）； 2740 磁层物理学：磁层结构和动力学； 2731 磁层物理学：磁层——外层；关键词: 行星磁层, 木星磁层, 场对准电流, 磁层结构
[1] The configuration of the magnetic field near 100 RJ in the dusk sector of the Jovian magnetosphere varies with distance from the equatorial current sheet. The changing twist out of meridian planes is consistent with flows that lag corotation near the equator but that may lead corotation at higher latitudes. Although a portion of the field perturbation may be produced by magnetopause currents, we argue that the observed sheared field structure requires field-aligned current flowing toward Jupiter’s ionosphere inside the magnetopause but beyond � 100 RJ. This current must include a portion of the return current of the system that enforces partial corotation of outward moving magnetospheric plasma and may also be fed by boundary layer currents of the region 1 type. We estimate the total current into the auroral ionosphere as � 6 MA, and this current would flow into a narrow band of latitude (<2� ) poleward of the main auroral oval. INDEX TERMS: 5737 Planetology: Fluid Planets: Magnetospheres (2756); 2756 Magnetospheric Physics: Planetary magnetospheres (5443, 5737, 6030); 2740 Magnetospheric Physics: Magnetospheric configuration and dynamics; 2731 Magnetospheric Physics: Magnetosphere—outer; KEYWORDS: planetary magnetosphere, Jupiter’s magnetosphere, field-aligned currents, magnetospheric configuration