The review is based on the investigation results of features and generation conditions of various non-linear phenomena in the high-latitude ionospheric F-region induced by the extraordinary polarized powerful HF radio waves. It examines the following: (1) artificial field-aligned irregularities (AFAI); (2) ducts of enhanced electron density; (3) narrowband (± 1 kHz of the heater frequency) stimulated electromagnetic emission (NSEE); (4) HF-induced Langmuir radio-induced and ion-acoustic plasma waves; (5) radio-induced optical emissions (RIOE) in the red and green lines of atomic oxygen. Features of non-linear phenomena induced by the ordinary (O-mode) and extraordinary (X-mode) HF pumping were compared, including nonresonance phenomena excited at high effective radiated power (ERP > 300 MW), when the pump wave is not reflected from the ionosphere. Prospects for development of research on ionospheric modification by powerful HF radio waves in Russia are briefly considered.

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Keywords: powerful HF radio wave, extraordinary polarization, ordinary polarization, high latitude ionosphere, nonlinear phenomena, artificial ionospheric irregularities, plasma waves, electron acceleration, duct, narrowband stimulated electromagnetic emission, radio-induced optical emission, nonresonance phenomena PACS: 41.20.Jb, 52.35.−g, 94.20.−y (all) DOI: 10.3367/UFNe.2026.03.040115 URL: https://ufn.ru/en/articles/2026/8/c/ Citation: Blagoveshchenskaya N F, Kalishin A S, Borisova T D, Vasilyev R V, Zherebtsov G A "Non-linear phenomena in the ionospheric F-region induced by extraordinary polarized powerful HF radio waves" Phys. Usp. 69 (8) (2026) Received: 29th, December 2025, revised: 19th, March 2026, accepted: 29th, March 2026 Оригинал: Благовещенская Н Ф, Калишин А С, Борисова Т Д, Васильев Р В, Жеребцов Г А «Нелинейные явления в F-области ионосферы при воздействии мощными радиоволнами КВ-диапазона необыкновенной поляризации» УФН 196 842–866 (2026); DOI: 10.3367/UFNr.2026.03.040115