Kil Hyosub, Paxton Larry J, Schaefer Robert K
The Johns Hopkins University Applied Physics Laboratory Laurel MD USA.
J Geophys Res Space Phys. 2022 May;127(5):e2021JA030121. doi: 10.1029/2021JA030121. Epub 2022 May 24.
We investigate the impact of conjugate photoelectrons (CPEs) on the topside (∼600 km altitude) ionosphere at low and midlatitudes using measurements of the ion temperature, density, and composition from the first Republic of China satellite during a period of the high to moderate solar activity (March 1999 to June 2004). Elevated ion temperatures and densities are observed in the dark Northern American-Atlantic sector during the December solstice and in the Australian sector during the June solstice. The oxygen ion fraction and density are also elevated at these locations. These observations indicate that photoelectrons from the conjugate hemisphere heat the local ionospheric plasma. The morphology of the ion temperature in the winter hemisphere is well represented by the solar zenith angle in the sunlit conjugate hemisphere. The CPE hypothesis for the observed ionospheric heating is confirmed by coincident nighttime enhancements of the far ultraviolet airglow measured by the Global Ultraviolet Imager onboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics satellite.
我们利用中华民国第一颗卫星在太阳活动从高到中等期间（1999年3月至2004年6月）对离子温度、密度和成分的测量，研究了共轭光电子（CPEs）对低纬度和中纬度地区顶侧（约600公里高度）电离层的影响。在12月冬至期间，在北美 - 大西洋黑暗区域以及6月冬至期间在澳大利亚区域观测到离子温度和密度升高。这些位置的氧离子分数和密度也升高。这些观测结果表明，来自共轭半球的光电子加热了当地电离层等离子体。冬季半球离子温度的形态可以通过日照共轭半球的太阳天顶角很好地表示。热层 - 电离层 - 中间层能量学与动力学卫星上搭载的全球紫外成像仪测量到的夜间远紫外气辉同时增强，证实了观测到的电离层加热的CPE假说。
