On the fine structure of medium energy electron fluxes in the auroral zone and related effects in the ionospheric D-region
On the fine structure of medium energy electron fluxes in the auroral zone and related effects in the ionospheric D-region
复制标题
极光区中能电子通量的精细结构及电离层D区的相关效应
DOI：
10.5194/angeo-28-1107-2010
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发表时间：
2010
影响因子：
1.9
通讯作者：
D. Evans
中科院分区：
文献类型：
--
作者：
J. Hargreaves;M. J. Birch;D. Evans
摘要。本研究基于极地轨道环境卫星在芬兰基尔皮斯jarvi成像测速仪立交点观测到的能量为bbbb30 keV和b>00 keV的捕获和沉淀电子的测量结果。这些卫星在850公里的太阳同步轨道上运行，以2秒的时间分辨率记录电子通量。测热计测量38.2兆赫的无线电波吸收，显示240公里视野范围内的空间模式。分析主要集中在两个方面。在发现卫星立交桥期间无线电波吸收与中能量电子通量之间的密切相关后，推导出经验关系，从而能够从当地时间的三个部分预测一个量与另一个量。结果表明，在一次穿越中观测到的小尺度变化基本上是空间的，而不是时间的。根据俯仰角散射理论，还考虑了其他性质，如光谱以及沉淀和捕获组分之间的关系。研究发现，这些特性和行为在很大程度上取决于一天中的时间。在正午扇区，沉淀通量和捕获通量通过平方律关系高度相关。
Abstract. This study is based on measurements of trapped and precipitated electrons of energy >30 keV and >100 keV observed by polar orbiting environmental satellites during overpasses of the imaging riometer at Kilpisjarvi, Finland. The satellites are in sun-synchronous orbits of about 850 km altitude, recording the electron fluxes at 2-s time resolution. The riometer measures the radiowave absorption at 38.2 MHz, showing the spatial pattern within a 240 km field of view. The analysis has focussed on two areas. Having found a close correlation between the radiowave absorption and the medium-energy electron fluxes during satellite overpasses, empirical relationships are derived, enabling one quantity to be predicted from the other for three sectors of local time. It is shown that small-scale variations observed during a pass are essentially spatial rather than temporal. Other properties, such as the spectra and the relation between precipitated and trapped components, are also considered in the light of the theory of pitch angle scattering by VLF waves. It is found that the properties and behaviour depend strongly on the time of day. In the noon sector, the precipitated and trapped fluxes are highly correlated through a square law relationship.