Cassini plasma spectrometer thermal ion measurements in Saturn's inner magnetosphere
Cassini plasma spectrometer thermal ion measurements in Saturn's inner magnetosphere
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DOI：
10.1029/2008ja013486
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发表时间：
2008-12
影响因子：
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通讯作者：
R. Wilson;Robert L. Tokar;M. Henderson;T. Hill;M. Thomsen;D. Pontius
中科院分区：
文献类型：
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作者：
R. Wilson;Robert L. Tokar;M. Henderson;T. Hill;M. Thomsen;D. Pontius
由两个各向异性的麦克斯韦分布物种H+和一个水族离子W+表示。在这一区域内，土星的磁层等离子体被显示为低于刚性自转的15%-30%，最小的分数滞后在7到9RS之间。有一个小的径向外流的建议，但这项研究的数据选择排除了交换注入事件的包括在内。离子密度与卡西尼等离子体波仪器非常吻合，这给了人们对正演模拟技术的信心。给出了包括密度、温度和速度在内的等离子体矩，以及密度和方位向速度的经验模型。水团温度各向异性T？/Tk在5.5RS附近有3~8的值，随着距离的增加，各向异性变小，但到10RS时仍不各向同性。讨论了这些结果对土星磁层质量负荷的影响，得出的结论是，等离子体源的一个重要部分位于本研究的5.5RS边界之内。
represented by two anisotropic Maxwellian distributed species, H + and a water group ion, W + . Saturn’s magnetospheric plasma is shown to subcorotate by 15–30% below rigid corotation within this region, with a minimum in fractional lag between 7 and 9 RS. There is a suggestion of a small radial outflow, but the selection of data for this study precluded the inclusion of interchange injection events. Ion densities are in excellent agreement with the Cassini plasma wave instrument, giving confidence in the forward modeling technique. Plasma moments including density, temperatures, and velocities are presented, along with empirical models for density and azimuthal velocity. Water group temperature anisotropies T?/Tk have values between 3 and 8 near 5.5 RS, becoming less anisotropic as distance increases, but are still not isotropic by 10 RS. The implications of these results for mass loading in the Saturnian magnetosphere are discussed, with the conclusion that an important fraction of the plasma source is located inside of the 5.5 RS boundary of this study.