Possible Detection of Titan's Ionosphere from Voyager 1 Radio Occultation Observations
Possible Detection of Titan's Ionosphere from Voyager 1 Radio Occultation Observations
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DOI：
10.1006/icar.1997.5831
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发表时间：
1995-06
期刊：
影响因子：
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通讯作者：
M. Bird;R. Dutta-Roy;S. Asmar;T. Rebold
中科院分区：
文献类型：
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作者：
M. Bird;R. Dutta-Roy;S. Asmar;T. Rebold
摘要对旅行者1号1980年掩星时记录的双频多普勒数据进行了新的分析，获得了土卫六电离层边缘探测的证据。Lindal等人的原始报告（1983，Icarus 53，348-363）仅给出了进入期间（晚上终结者）的峰值电子密度上限3000 cm-3和外出期间（早上终结者）的峰值电子密度上限5000 cm-3。双频侵入数据意味着泰坦上电离层在1180 ± 150公里高度的最大电子密度为2400 ± 1100 cm −3。出口数据被确定为对该分析的有限使用，因为X波段信号仅被接收了几秒钟。尽管如此，一个明显的电离层峰值显示在S波段数据的入口和出口。该电离层的高度和峰值密度与数值模型的预期吻合良好，该模型调用光电离和高能电子碰撞。
Abstract Evidence for a marginal detection of the Titan ionosphere has been obtained from a new analysis of the dual-frequency Doppler data recorded during the Voyager 1 occultation in 1980. The original report by Lindal et al. (1983, Icarus 53, 348–363) gave only upper bounds on the peak electron density of 3000 cm −3 during ingress (evening terminator) and 5000 cm −3 during egress (morning terminator). The dual-frequency ingress data imply a maximum electron density of 2400 ± 1100 cm −3 for Titan's upper ionosphere at an altitude of 1180 ± 150 km. The egress data were determined to be of limited use for this analysis because the X-band signal was received for only a few seconds. Nevertheless, a distinct ionospheric peak is revealed in the S-band data for both ingress and egress. The height and peak density of this ionized layer are in good agreement with expectations from numerical models that invoke photoionization and energetic electron impacts.