Abstract

In this paper, we present the results of experimental studies of phenomena in the high-latitude upper (F-region) ionosphere caused by the impact of high-power HF radio waves of ordinary (O-mode) polarization at heating frequencies f_H that significantly exceed the critical frequency of the F2 layer (f_H – fоF2 = 0.9–1.1 MHz). The results are based on experimental data obtained at the EISCAT/Heating HF heating facility in Tromsø, northern Norway (69.6° N, 19.2° E). In the experiments, a high-power HF radio wave of the O-polarization range was emitted in the direction of the magnetic zenith with a maximum effective radiation power of 350–550 MW. It was found for the first time that under conditions when a powerful HF radio wave of the O-polarization was not reflected from the ionosphere, ducts of increased electron density Ne are formed, and small-scale artificial ionospheric inhomogeneities and narrow-band (within a ±1-kHz band relative to the heating frequency) artificial radio emission of the ionosphere that are recorded at a distance of ~1200 km from the heating facility are generated. The characteristics of small-scale artificial ionospheric irregularities and the spectral structure of artificial radio emission of the ionosphere with alternative O/X heating to the magnetic zenith at frequencies significantly exceeding the critical frequency of the F2 layer are compared. It was established that, in general, their behavior has the same character, but the evolution of the development of the considered phenomena during O and X heating is different.

中文翻译：

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F2层临界频率以上强高频无线电波作用下高纬度F区电离层现象

摘要

在本文中，我们介绍了高纬度上层（F区）电离层现象的实验研究结果，这些现象是由普通（O模式）偏振的高功率高频无线电波在加热频率f _{H的影响引起的，显着超过}F 2 层的临界频率（f _H – fоF 2 = 0.9–1.1 MHz）。结果基于在挪威北部特罗姆瑟（北纬 69.6°，东经 19.2°）的 EISCAT/Heating 高频加热设施获得的实验数据。实验中，向磁天顶方向发射O极化范围的高功率高频无线电波，最大有效辐射功率为350-550 MW。首次发现，在电离层未反射强大的O极化高频无线电波的情况下，会形成电子密度Ne增加的导管，并产生小规模的人工电离层不均匀性和窄带（以内）产生电离层的人工无线电发射（相对于加热频率±1kHz频带），该发射是在距离加热设施约1200公里处记录的。比较了小尺度人工电离层不规则性的特征和电离层人工无线电发射的频谱结构，其中交替O/X加热到磁天顶，频率显着超过F 2层的临界频率。可以确定的是，一般来说，它们的行为具有相同的特征，但在 O 和 X 加热过程中所考虑的现象的发展演变是不同的。