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PACS: 01.60.+q DOI: 10.3367/UFNe.2026.04.040129 URL: https://ufn.ru/en/articles/2026/7/f/ Citation: Bykov A M, Dogel’ V A, Zelenyi L M, Zirakashvili V N, Ivanchik A V, Kocharovskii V V, Krymskii G F, Kuzmichev L A, Levenfish K P, Postnov K A, Starodubtsev S A, Yakovlev D G "In memory of Igor Nikolaevich Toptygin" Phys. Usp. 69 (7) (2026) Accepted: 28th, April 2026 I.N. Toptygin is author of Physics-Uspekhi