On the steady‐state assumption for the energy distribution function of the nonthermal N(4S) atoms and the efficiency of NO production by these atoms in the terrestrial thermosphere
On the steady‐state assumption for the energy distribution function of the nonthermal N(4S) atoms and the efficiency of NO production by these atoms in the terrestrial thermosphere
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关于非热N(4S)原子能量分布函数的稳态假设以及这些原子在陆地热层中产生NO的效率
DOI：
10.1029/97gl03258
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
J. Duff
中科院分区：
文献类型：
--
作者：
H. Dothe;R. Sharma;J. Duff
通过求解与时间相关的玻尔兹曼方程，计算当地时间 1400 小时时海拔大于 100 公里的 N(4S) 原子的与时间相关的能量分布函数 (EDF)。在时间 t=0 时，时间相关的源和汇被切换为 N(4S) 原子的麦克斯韦-玻尔兹曼分布，并且通过求解玻尔兹曼方程来跟踪 EDF 的时间依赖性。研究发现，EDF 的非麦克斯韦尾在 0.01 秒内达到稳态，使得在建立稳态之前与 O2 反应的新生 N(4S) 原子的比例小于 1%。建立稳态后，EDF 的非麦克斯韦尾每秒产生的 NO 分子数量至多约为源中 N(4S) 原子数量的 3%。最后一个分数通常称为“NO 反应效率”，大约比最近文献中给出的要小一个数量级。这项研究的一个重要结果是，模型计算出的中间层和热层中的 NO 仍然少于测量值。
The time dependent energy distribution functions (EDF) of N(4S) atoms for altitudes greater than 100 km at 1400 hr local time are calculated by solving the time dependent Boltzmann equation. At time t=0 the time dependent sources and sinks are switched on into a Maxwell‐Boltzmann distribution of N(4S) atoms and the time dependence of the EDF is followed by solving the Boltzmann equation. It is found that the non‐Maxwellian tail of the EDF reaches a steady‐state in 0.01 s giving the fraction of nascent N(4S) atoms that react with O2 before the establishment of steady‐state to be less than 1%. The number of NO molecules produced per second, after the establishment of steady‐state, by the non‐Maxwellian tail of the EDF is at most about 3% of the number of N(4S) atoms in the sources. The last fraction, often referred to as “NO reaction efficiency”, is about an order of magnitude smaller than that given in recent literature. An important consequence of this study is that the models still calculate less NO in the mesosphere and lower thermosphere than is measured.