太阳活动周24期间D区电离层电子密度变化建模
Modeling of the variability of D-region ionospheric electron density during solar cycle-24
- Indian Centre for Space Physics（印度空间物理中心）
- Department of Atmospheric Sciences, University of Calcutta（加尔各答大学大气科学系）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文通过数值建模，研究第24太阳活动周期间D区电离率与电子密度变化，发现其呈现与太阳黑子数一致的“双峰”特征，并验证了与IRI-2020的一致性，为后续VLF观测研究奠定基础。
AI中文摘要：
太阳活动周变化对地球大气，特别是电离层的影响，在空间科学和空间天气研究领域尤为引人关注。本文通过数值研究，详细定量探讨了低电离层特性随太阳活动周的变化。首先，我们针对第24太阳活动周（C24）期间，对来自电离源（即（a）太阳极紫外（EUV）辐射（包括莱曼-阿尔法辐照）和（b）太阳X射线辐照）的各自贡献，建模并比较了D区总电离率（q）。随后，我们利用这些电离率计算了电子密度（Ne）廓线。我们报告了在C24整个期间电离率和电子密度廓线存在显著的太阳活动周变化。我们使用太阳黑子数（SPN）廓线来佐证C24期间Ne廓线的更精细细节。对于两个不同地理坐标上方的D区段，我们报告Ne廓线呈现一致的“双峰”特征，这与C24期间的SPN廓线非常相似。作为下一步验证，我们将建模的Ne廓线与IRI-2020对应的Ne廓线（Ne,iris）进行比较，发现它们的总体趋势一致。最后，我们讨论了D区在C24期间以Ne为表征的响应。这项工作为我们后续利用甚低频（VLF）观测研究D区对太阳活动周变化的响应奠定了基础。
英文摘要：
Solar cycle variation of earth's atmosphere, particularly the ionosphere is of particular interest in the field of space science and space weather studies. In this article, we present the outcome of our detailed quantitative study on solar cycle variation of lower ionospheric properties using numerical investigation. First, we seek to model and compare the collective D-region ionization rates (q's) due to the individual contributions from the ionizing sources, namely, (a) solar extreme ultraviolet (EUV) radiation including the Lyman-alpha irradiation and (b) solar X-ray irradiation throughout the 24th solar cycle (C24). Then, we compute the electron density (Ne) profiles using the ionization rates. We report significant solar cycle variation in ionization rate and electron density profiles for the entire span of C24. We use the sunspot number (SPN) profile to substantiate the finer details of Ne profile during C24. For the segments of the D-region above two different geographic coordinates, we report that Ne profiles show a consistent "dual peak" nature. It is very similar to the SPN profile during C24. As a next-order validation, we compare our modeled Ne profiles with their IRI-2020 counterpart (Ne,iris). Their overall trends are found to be in agreement. Finally, we discuss the response of the D-region in terms of Ne due to C24. The work lays the foundation for our upcoming studies on D-region response to solar cycle variation with Very Low Frequency (VLF) observation.
