Energy distribution of energetic O+ precipitation into the atmosphere
Energy distribution of energetic O+ precipitation into the atmosphere
复制标题
大气中高能 O 沉淀的能量分布
DOI：
10.1029/92ja00228
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发表时间：
1992
影响因子：
--
通讯作者：
C. Meng
中科院分区：
文献类型：
--
作者：
M. Ishimoto;G. Romick;C. Meng
环电流离子密度的主动磁层粒子示踪剂探测器CCE卫星的测量表明，一个大通量的高能（几十千电子伏）O+沉淀在中纬度大气中的主要磁暴。NOAA 6号卫星上的质谱仪（>30 keV）在一次非常大的地磁暴期间，在52°不变纬度测量到30 ergs cm−2 s−1的离子通量。为了计算大气响应降水的高能O+通量，我们已经修订了O+运输模型，包括能量高达200千电子伏。本文介绍了该模型对各种单能O+通量的估计截面和模型大气的敏感性。计算结果表明：（1）大部分入射能量立即转化为大气加热;（2）逃逸粒子总数小于入射粒子总数，这与以往模式的结果相反;（3）加热和电离峰值高度随入射能量的不同而变化，在104 ~ 300 km之间。结果是最敏感的估计微分散射截面在大散射角。在可能范围的两个极端使用前向散射截面导致非常不同的能量分配和峰值电离和加热的高度（相差多达80公里）。MSIS-86模式大气极端参数值引起的能量分配的变化不大，但在模型中的原子氧密度（F10.7指数= 70和210）的大变化改变了峰值加热和电离高度为低能量入射O+（几千电子伏）50公里。
Measurements of ring current ion densities by the Active Magnetospheric Particle Tracer Explorers CCE satellite suggest that a large flux of energetic (tens of keV) O+ precipitates in the mid-latitude atmosphere during major geomagnetic storms. The mass spectrometer (>30 keV) on board the NOAA 6 satellite measured an ion flux of 30 ergs cm−2 s−1 at 52° invariant latitude during a very large geomagnetic storm. To calculate atmospheric response to precipitation of the energetic O+ fluxes, we have revised an O+ transport model to include energies up to 200 keV. The model's sensitivity to the estimated cross sections and model atmospheres for various monoenergetic O+ fluxes are presented in this paper. Calculation of the atmospheric response to O+ precipitation shows that (1) most of the incident energy is immediately transformed into atmospheric heating, (2) the total number of escape particles is smaller than the total number of incident particles, in contrast to the results of previous models, and (3) the peak heating and ionization altitudes vary from 104 to 300 km depending on the incident energy. The results are most sensitive to the estimated differential scattering cross sections at large scattering angles. The use of forward scattering cross sections at both extremes of the possible range results in very different energy allocations and altitudes of peak ionization and heating (a difference of as much as 80 km). The MSIS-86 model atmosphere with extreme parametric values caused little change in the energy allocation, but the large variation in the model atomic oxygen density (F10.7 index = 70 and 210) alters the peak heating and ionization altitude for low-energy incident O+ (a few keV) by 50 km.