Energetic electron precipitation and the NO abundance in the upper atmosphere: A direct comparison during a geomagnetic storm
Energetic electron precipitation and the NO abundance in the upper atmosphere: A direct comparison during a geomagnetic storm
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高能电子沉淀和高层大气中的 NO 丰度：地磁风暴期间的直接比较
DOI：
10.1029/2004ja010485
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发表时间：
2004
影响因子：
--
通讯作者：
N. Østgaard
中科院分区：
文献类型：
--
作者：
C. Sætre;J. Stadsnes;H. Nesse;A. Aksnes;S. Petrinec;C. Barth;D. Baker;R. Vondrak;N. Østgaard
[1] 直接将地球高层大气中 96 至 150 公里高度处的一氧化氮 (NO) 密度与沉淀高能电子的能量沉积进行比较。这些比较是在 1998 年 5 月 2 日地磁风暴事件开始时进行的。电子能量来自极地航天器上极地电离层 X 射线成像实验 (PIXIE) 的 X 射线轫致辐射观测结果。 NO 密度的测量是由学生一氧化氮探测器 (SNOE) 在白天通过测量 NO g 波段的气辉光谱特征来进行的。由于电子降水的很大一部分发生在夜间，并且考虑到NO的长寿命，我们将X射线数据积累在地理方框中。这使我们能够跟踪夜间和早晨特定区域的总能量沉积的发展。与理论预测一致，我们发现由于电子沉淀，高纬度地区 NO 增加。在106公里海拔处，即NO强度和沉淀电子能量峰值的平均高度，83%的NO密度是由电子沉淀产生的。在这个高度，我们发现电子沉淀导致每 keV 沉积能量产生 8 个 NO 分子。数据的比较还显示了水平中性风的影响。在 100 公里以上，NO 密度峰值向电子能量沉积峰值的赤道方向移动。索引术语：2716 磁层物理学：高能粒子，沉淀； 2736 磁层物理学：磁层/电离层相互作用； 2437 电离层：电离层动力学； 2407 电离层：极光电离层（2704）； 2455 电离层：粒子降水；关键词: PIXIE, SNOE, 一氧化氮, 电子沉淀
[1] Nitric oxide (NO) densities at heights between 96 and 150 km in the Earth’s upper atmosphere are directly compared with the energy deposition from precipitating energetic electrons. The comparisons are done for the beginning of a geomagnetic storm event on 2 May 1998. The electron energy is derived from X-ray bremsstrahlung observations from the Polar Ionospheric X-ray Imaging Experiment (PIXIE) on board the Polar spacecraft. Measurements of the NO density are performed by the Student Nitric Oxide Explorer (SNOE) on the dayside by measuring airglow spectral features of the NO g-band. Since a significant part of the electron precipitation takes place during the night, and considering the long lifetime of NO, we have accumulated the X-ray data in geographical boxes. This enables us to follow the development of the total energy deposition over a specific area during the night and morning hours. In agreement with theoretical predictions we find an increase in NO at higher latitudes due to electron precipitation. At 106 km altitude, which is found to be the average altitude of the peak values of both NO intensity and precipitating electron energy, 83% of the NO density is produced by electron precipitation. At this altitude we find that the electron precipitation results in the production of 8 NO molecules per keV deposited energy. The comparison of the data also shows effects of a horizontal neutral wind. Above 100 km the peak in NO density is displaced equatorward of the peak in electron energy deposition. INDEX TERMS: 2716 Magnetospheric Physics: Energetic particles, precipitating; 2736 Magnetospheric Physics: Magnetosphere/ ionosphere interactions; 2437 Ionosphere: Ionospheric dynamics; 2407 Ionosphere: Auroral ionosphere (2704); 2455 Ionosphere: Particle precipitation; KEYWORDS: PIXIE, SNOE, nitric oxide, electron precipitation