Ion transport in Titan's upper atmosphere
Ion transport in Titan's upper atmosphere
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DOI：
10.1029/2009ja014563
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发表时间：
2010-06-23
影响因子：
2.8
通讯作者：
Dougherty, M. K.
中科院分区：
文献类型：
--
作者：
Cui, J.;Galand, M.;Dougherty, M. K.
基于一个组合的卡西尼数据集，包括离子中性质谱仪，无线电等离子体波科学，并在9次近距离接触的卡西尼飞船与土卫六磁力计测量，我们调查的电子（或总离子）在1250和1600公里之间的卫星上电离层的分布。将测得的电子分布与扩散平衡的电子分布进行比较，表明土卫六的全球离子逃逸，总离子损失率类似于（1.7 +/- 0.4）x 10（25）s（-1）。在离子输送的显着的日变化暗示的数据，其特征在于在阳面和离子流入在阴面的离子流出，特别是低于类似1400公里。这被解释为昼夜离子传输的结果，水平传输速率估计类似于（1.4 +/- 0.5）x 10（24）s（-1）。这种离子流很可能是土卫六夜侧电离层的重要来源，如Cui等人[2009 a]所提出的。
Based on a combined Cassini data set including Ion Neutral Mass Spectrometer, Radio Plasma Wave Science, and Magnetometer measurements made during nine close encounters of the Cassini spacecraft with Titan, we investigate the electron ( or total ion) distribution in the upper ionosphere of the satellite between 1250 and 1600 km. A comparison of the measured electron distribution with that in diffusive equilibrium suggests global ion escape from Titan with a total ion loss rate of similar to(1.7 +/- 0.4) x 10(25) s(-1). Significant diurnal variation in ion transport is implied by the data, characterized by ion outflow at the dayside and ion inflow at the nightside, especially below similar to 1400 km. This is interpreted as a result of day-to-night ion transport, with a horizontal transport rate estimated to be similar to(1.4 +/- 0.5) x 10(24) s(-1). Such an ion flow is likely to be an important source for Titan's nightside ionosphere, as proposed in Cui et al. [2009a].