Miller Steve, Stallard Tom, Smith Chris, Millward George, Melin Henrik, Lystrup Makenzie, Aylward Alan
Atmospheric Physics Laboratory, Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK.
Philos Trans A Math Phys Eng Sci. 2006 Nov 15;364(1848):3121-35; discussion 3136-7. doi: 10.1098/rsta.2006.1877.
We present a review of recent developments in the use of H3+ molecular ion as a probe of physics and chemistry of the upper atmospheres of giant planets. This ion is shown to be a good tracer of energy inputs into Jupiter (J), Saturn (S) and Uranus (U). It also acts as a 'thermostat', offsetting increases in the energy inputs owing to particle precipitation via cooling to space (J and U). Computer models have established that H3+ is also the main contributor to ionospheric conductivity. The coupling of electric and magnetic fields in the auroral polar regions leads to ion winds, which, in turn, drive neutral circulation systems (J and S). These latter two effects, dependent on H3+, also result in very large heating terms, approximately 5 x 10(12) W for Saturn and greater than 10(14) W for Jupiter, planet-wide; these terms compare with approximately 2.5 x 10(11) W of solar extreme UV absorbed at Saturn and 10(12) W at Jupiter. Thus, H3+ is shown to play a major role in explaining why the temperatures of the giant planets are much greater (by hundreds of kelvin) at the top of the atmosphere than solar inputs alone can account for.
我们对使用H3 +分子离子作为探测巨行星高层大气物理和化学性质的最新进展进行了综述。该离子被证明是木星（J）、土星（S）和天王星（U）能量输入的良好示踪剂。它还起到“恒温器”的作用，通过向太空冷却来抵消由于粒子沉降导致的能量输入增加（木星和天王星）。计算机模型已经确定，H3 +也是电离层电导率的主要贡献者。极光极地地区电场和磁场的耦合导致离子风，进而驱动中性环流系统（木星和土星）。后两种依赖于H3 +的效应也会产生非常大的加热项，土星全球范围内约为5×10¹²瓦，木星则大于10¹⁴瓦；这些项与土星吸收的约2.5×10¹¹瓦太阳极紫外辐射以及木星吸收的10¹²瓦相比。因此，H3 +在解释为什么巨行星大气顶部的温度比仅由太阳输入所能解释的温度高得多（高出数百开尔文）方面起着重要作用。
