Structure, stability and evolution of Saturn's rings
Structure, stability and evolution of Saturn's rings
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DOI：
10.1038/309333a0
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发表时间：
1984-05
期刊：
影响因子：
64.8
通讯作者：
F. Bridges;A. Hatzes;D. Lin
中科院分区：
文献类型：
--
作者：
F. Bridges;A. Hatzes;D. Lin
最近从旅行者号航天器和地面测量获得的数据表明：（1）环的厚度最多为150米（参考文献1），而且可能要小好几倍2，3;（2）环主要由大小从厘米到米的冰粒组成4;（3）环被细分为大量小环，其径向尺寸从10公里到旅行者航天器相机的几米分辨率不等5;（4）B环包含非常多的光学深度变化（0.6-3）。这种行为基本上是由环中冰粒子的碰撞特性决定的。在这里，我们报告了一些初步的结果，从实验设计来测量的恢复系数的冰粒碰撞的冲击速度有关的土星环。我们将这些结果应用到土星环的简单动力学模型中，并推断土星环的厚度为2.5米。我们还表明，光学厚度<0.5的区域，如B环，是不稳定的粘性扩散。这种不稳定性可能是B环中光学深度变化的原因。
Recent data obtained from the Voyager spacecrafts and ground-based measurements indicate: (1) the rings have a thickness of at most 150 m (ref. 1) and probably several times less2,3; (2) the rings are mostly composed of ice particles ranging from centimetres to metres in size4; (3) the rings are subdivided into a large number of ringlets with a radial dimension ranging from 10-km down to the several metres resolution of the Voyager spacecraft's camera5; (4) the B ring contains very many optical depth variations (0.6–3)3. This behaviour is essentially determined by the collisional properties of the rings' ice particles. Here we report some preliminary results from an experiment designed to measure the coefficient of restitution of ice particles colliding at impact velocities relevant to Saturn's rings. We apply these results to simple dynamical models for Saturn's rings and deduce the rings' thickness to be ≺5 m. We also show that regions with optical depth <0.5, such as the B ring, are unstable to viscous diffusion. Such an instability may be the cause of optical depth variations in the B ring.