TY JOUR TI Studying the small-scale structure of a polarization jet during the April 20, 2018 geomagnetic storm KW polarization jet KW subauroral ionosphere KW geomagnetic activity KW satellite data JO Solar-Terrestrial Physics AU Sinevich, A.A. AU Chernyshov, A.A. AU Chugunin, D.V. AU Miloch, W.J. AU Mogilevsky, M.M. PY 2021 IS 7 PB INFRA-M Academic Publishing LLC.