Fillius W, Ip W H, McIlwain C E
Science. 1980 Jan 25;207(4429):425-31. doi: 10.1126/science.207.4429.425.
Pioneer 11 has made the first exploration of the magnetosphere and trapped radiation belts of Saturn. Saturn's magnetosphere is intermediate in size between Earth's and Jupiter's, with trapped particle intensities comparable to Earth's. The outer region of Saturn's magnetosphere contains lower energy radiation and is variable with time; the inner region contains higher energy particles. The pitch angle distributions show a remarkable variety of field-aligned and locally mirroring configurations. The moons and especially the rings of Saturn are effective absorbers of trapped particles; underneath the rings, the trapped radiation is completely absorbed. We confirm the discovery of a new ring, called the F ring, a new division, the Pioneer division, and a moon, called 1979 S 2. The latter has probably been seen from Earth. There may be evidence for more bodies like 1979 S 2, but at this stage the interpretation of the data is ambiguous. Using particle diffusion rates, we estimate that the cross-sectional area of the F ring is > 7 x 10(13) square centimeters and that the opacity is > 10(-5). Cosmic-ray albedo neutron decay should be looked into as a source of energetic particles in the inner magnetosphere of Saturn.
“先驱者11号”首次对土星的磁层和捕获辐射带进行了探测。土星磁层的大小介于地球和木星之间，捕获粒子的强度与地球相当。土星磁层的外层区域包含能量较低的辐射，且随时间变化；内层区域包含能量较高的粒子。俯仰角分布呈现出各种显著的场向和局部镜像配置。土星的卫星，尤其是土星环，是捕获粒子的有效吸收体；在土星环下方，捕获辐射被完全吸收。我们证实了新环（称为F环）、新分区（先驱者分区）以及一颗卫星（称为1979 S 2）的发现。后者可能已被地球上的观测者看到。可能有证据表明存在更多类似1979 S 2的天体，但在此阶段，数据的解释尚不明确。利用粒子扩散速率，我们估计F环的横截面积大于7×10¹³平方厘米，不透明度大于10⁻⁵。宇宙射线反照率中子衰变应作为土星内磁层高能粒子的一个来源进行研究。
