Taylor H A, Brinton H C, Bauer S J, Hartle R E, Donahue T M, Cloutier P A, Michel F C, Daniell R E, Blackwell B H
Science. 1979 Feb 23;203(4382):752-4. doi: 10.1126/science.203.4382.752.
The first in situ measurements of the composition of the ionosphere of Venus are provided by independent Bennett radio-frequency ion mass spectrometers on the Pioneer Venus bits and orbiter spacecraft, exploring the dawn and duskside regions, respectively. An extensive composition of ion species, rich in oxygen, nitrogen, and carbon chemistry is idenitified. The dominant topside ion is O(+), with C(+), N(+), H(+), and He(+) as prominent secondary ions. In the lower ionosphere, the ionzization peak or F(1) layer near 150 kilometers reaches a concentration of about 5 x l0(3) ions per cubic centimeter, and is composed of the dominant molecular ion, O(2)(+), with NO(+), CO(+), and CO(2)(+), constituting less than 10 percent of the total. Below the O(+) peak near 200 kilometers, the ions exhibit scale heights consistent with a neutral gas temperature of about 180 K near the terminator. In the upper ionosphere, scale heights of all species reflect the effects of plasma transport, which lifts the composition upward to the often abrupt ionopause, or thermal ion boundary, which is observed to vary in height between 250 to 1800 kilometers, in response to solar wind dynamics.
先锋金星号探测器和轨道飞行器上的独立贝内特射频离子质谱仪首次对金星电离层的成分进行了原位测量，它们分别探测了金星的晨侧和昏侧区域。现已识别出种类丰富的离子成分，其中富含氧、氮和碳化学物质。电离层顶部的主要离子是O(+)，C(+)、N(+)、H(+)和He(+)是主要的次要离子。在较低的电离层中，150公里附近的电离峰值或F(1)层的离子浓度达到每立方厘米约5×10(3)个离子，主要由分子离子O(2)(+)组成，NO(+)、CO(+)和CO(2)(+)占总量不到10%。在200公里附近的O(+)峰值以下，离子的标高与近终止区约180K的中性气体温度一致。在较高的电离层中，所有种类离子的标高反映了等离子体输运的影响，这种输运将成分向上提升至通常较为陡峭的电离层顶或热离子边界，观测发现该边界的高度在250至1800公里之间变化，以响应太阳风动力学。
