论文标题
使用巨大的Metrewave射程望远镜（GMRT）在亚GHz频率上研究赤道电离层
Study of the equatorial ionosphere using the Giant Metrewave Radio Telescope (GMRT) at sub-GHz frequencies
论文作者
论文摘要
旨在观察宇宙中天体物理物体的无线电干涉仪也可以用于研究地球的电离层。诸如巨大的大声射电望远镜（GMRT）之类的无线电干涉仪在离电层总电子含量（TEC）中检测到比传统的电离层探针（如全球导航卫星系统（GNSS））的空间尺度上的变化。 GMRT（紧凑的核心和延伸臂）的混合配置及其地理位置使该干涉仪成为探索赤道电离异常（EIA）和磁性赤道之间敏感区域的绝佳候选者。对于这项工作，从午夜到避孕后（$ \ sim $ \，9小时）观察到明亮的无线电源3C68.2，以研究太阳能米尼马的电离层活动。这项研究介绍了数据降低和处理技术，以测量差异TEC（$δ\ rm {tec} $）之间的差异，其精度为$ 1 \ times10^{ - 3} $ tecu。此外，使用这些$δ\ rm {tec} $测量值，我们展示了在二维TEC TEC梯度表面上在完整阵列和微尺度变化上计算TEC梯度的技术。这些变化具有良好的探测电离层等离子体，尤其是在夜间。我们的研究首次报告了GMRT检测电离层活性的能力。与先前对VLA，Lofar和MWA的研究相比，我们的结果验证了GMRT上的电离层更为活跃，这是由于其在磁赤道附近的位置而预期的。
Radio interferometers, which are designed to observe astrophysical objects in the universe, can also be used to study the Earth's ionosphere. Radio interferometers like the Giant Metrewave Radio Telescope (GMRT) detect variations in ionospheric total electron content (TEC) on a much wider spatial scale at a relatively higher sensitivity than traditional ionospheric probes like the Global Navigation Satellite System (GNSS). The hybrid configuration of the GMRT (compact core and extended arms) and its geographical location make this interferometer an excellent candidate to explore the sensitive regions between the northern crest of the Equatorial Ionization Anomaly (EIA) and the magnetic equator. For this work, a bright radio source, 3C68.2, is observed from post-midnight to post-sunrise ($\sim$\,9 hours) to study the ionospheric activities at solar-minima. This study presents data reduction and processing techniques to measure differential TEC ($δ\rm{TEC}$) between the set of antennas with an accuracy of $1\times10^{-3}$ TECU. Furthermore, using these $δ\rm{TEC}$ measurements, we have demonstrated techniques to compute the TEC gradient over the full array and micro-scale variation in two-dimensional TEC gradient surface. These variations are well equipped to probe ionospheric plasma, especially during the night-time. Our study, for the first time, reports the capability of the GMRT to detect ionospheric activities. Our result validates, compared to previous studies with VLA, LOFAR and MWA, the ionosphere over the GMRT is more active, which is expected due to its location near the magnetic equator.
