lensing from small-scale travelling ionospheric disturbances observed using lofar
lensing from small-scale travelling ionospheric disturbances observed using lofar
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DOI：
10.1051/swsc/2022030
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发表时间：
2022-09
影响因子：
3.3
通讯作者：
Ben Boyde;A. Wood;G. Dorrian;Richard A Fallows;D. Themens;J. Mielich;S. Elvidge;M. Mevius;P. Zucca;B. Dabrowski;A. Krankowski;C. Vocks;M. Bisi
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文献类型：
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作者：
Ben Boyde;A. Wood;G. Dorrian;Richard A Fallows;D. Themens;J. Mielich;S. Elvidge;M. Mevius;P. Zucca;B. Dabrowski;A. Krankowski;C. Vocks;M. Bisi
使用低频阵列（LOFAR）在2018年9月15日10：15至11：48 UT之间在大约25-65 MHz的带宽上进行的观测包含电离层起源的离散伪周期特征。这些特征发生的时间大约为10分钟，总共持续大约一个小时。它们强烈地依赖于频率，在时间上向较低频率显著加宽，并且显示衍射条纹的重叠图案。通过将电离层建模为包含波状扰动的薄相位屏，我们能够复制观测结果，这表明它们与小尺度旅行电离层扰动（TID）有关。这个模型表明，这里观察到的特征需要一个低海拔的紧凑的无线电源，并且所讨论的TID或TID的波长约为30 km。几个特征表明存在与理想化正弦波形的偏差。这些结果表明LOFAR有能力识别和探测小尺度电离层结构。
Observations made using the LOw Frequency ARray (LOFAR) between 10:15 and 11:48 UT on the 15th of September 2018 over a bandwidth of approximately 25-65 MHz contain discrete pseudo-periodic features of ionospheric origin. These features occur with a period of approximately ten minutes and collectively last roughly an hour. They are strongly frequency dependent, broadening significantly in time towards the lower frequencies, and show an overlaid pattern of diffraction fringes. By modelling the ionosphere as a thin phase screen containing a wave-like disturbance, we are able to replicate the observations, suggesting that they are associated with small-scale travelling ionospheric disturbances (TIDs). This modelling indicates that the features observed here require a compact radio source at a low elevation, and that the TID or TIDs in question have a wavelength ~30 km. Several features suggest the presence of deviations from an idealised sinusoidal wave form. These results demonstrate LOFAR's capability to identify and characterise small-scale ionospheric structures.