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首页> 外文期刊>Journal of Geophysical Research, A. Space Physics: JGR >On the source of Pc1-2 waves in the plasma mantle
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On the source of Pc1-2 waves in the plasma mantle

机译:Pc1-2波在等离子体源的地幔

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Several ground-based observational studies have reported unstructured Pc1-2 waves near and poleward of the dayside cusp. Dyrud et al. (1997) were the first to suggest that these waves originated in the high-altitude plasma mantle. We report here on simultaneous field and particle observations from the Polar satellite and from ground magnetometer data that confirm the presence of these “mantle” waves and characterize the ion distributions associated with them. Unstructured Pc1-2 waves were found to occur during 45% of the available passes of Polar across the mantle during the interval March–May 2000, during which time the orbit of Polar was near local noon as it crossed these latitudes. Poynting vector calculations using Polar electric and magnetic field data show a mixture of upward and downward energy flux in the cusp but consistently downward flux when mantle waves are observed. This is consistent with earlier observations that ground-based magnetometers can detect such mantle waves but not the more intense wave activity observed by spacecraft in the middle- and low-altitude cusp. In situ particle observations from the Hydra instrument appear to confirm the generation mechanism suggested by Dyrud et al. that cusp particles mirroring at low altitudes and then traveling outward in the plasma mantle poleward of the cusp are the source of the free energy for these waves. Quantitative estimates of ion cyclotron instability of the observed ion distributions suggest they are stable at the ≤9 RE altitudes traversed by Polar but may be reasonably inferred to be unstable in the exterior mantle, a location consistent with their observed frequency.
机译:几个地面观测研究非结构化Pc1-2波附近和报道向极的光面的尖端。首先表明,这些波起源于高空等离子地幔。报告在同步场和粒子从极地卫星和观察地面磁力仪数据确认这些“衣钵”波和描述与他们相关的离子分布。非结构化Pc1-2波被发现在45%的可用的传递的极地在地幔中间隔高于32000年,在此期间极地的轨道附近的当地中午它越过这些纬度。坡印亭矢量的计算使用极性电和磁场数据显示向上的混合物和下行能量通量在尖端当地幔波持续下行流量观察到。观察地面磁力计可以检测这些地幔波而不是更强烈波活动观测到宇宙飞船中产阶级和低空尖端。观察从九头蛇似乎工具确认建议的产生机制Dyrud等人,尖端粒子镜像在低高度,然后向外旅行等离子体地幔向极尖端的来源这些波的自由能。估计的离子回旋不稳定观察到离子分布显示它们稳定在极地的≤9再保险海拔遍历但可以合理推断是不稳定的外部地幔,位置一致他们观察到的频率。

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