Science. 1979 Feb 23;203(4382):765-8. doi: 10.1126/science.203.4382.765.
Fourteen profiles of electron density in the ionosphere of Venus were obtainecd by the dual-frequency radio occulation method with the Pioneer Venus orbiter between 5 and 30 December 1978. The solar zenith angles for these measurements were between about 85 degrees and 92 degrees , and the latitudes ranged from about 81 degrees to 88 degrees (ecliptic north). In addition to the expected decreasein peak electron density from about 1.5 x 10(3) to 0.5 x 10(3) per cubic centimeter with increasing solar zenith angle, a region of almost constant electron density above about 250 kilometers was observed. The ionopause height varies from about 300 to 700 kilometers and seems to be influenced by diurnal changes in solar wind conditions. The structures of the profiles are consistent with models in which O(2)(+) dominates near the ionization peak and is replaced by O(+) at higher altitudes.
1978 年 12 月 5 日至 30 日，先驱者金星轨道飞行器利用双频无线电掩星法获得了金星电离层的 14 个电子密度剖面。这些测量的太阳天顶角约为 85 度至 92 度，纬度范围约为 81 度至 88 度（黄道北）。除了预期的随着太阳天顶角的增加，峰值电子密度从每立方厘米约 1.5 x 10(3)下降到 0.5 x 10(3)之外，还观察到了一个在大约 250 公里以上几乎恒定的电子密度区域。离子层顶高度从大约 300 公里到 700 公里不等，似乎受到太阳风条件昼夜变化的影响。这些剖面的结构与模型一致，在模型中，O(2)(+)在电离峰附近占主导地位，而在更高的高度则被 O(+)取代。
