TY JOUR TI On the formation of the F1 layer during sudden stratospheric warming events KW ionosphere KW low atmosphere KW stratospheric warming KW F1 layer JO Solnechno-Zemnaya Fizika AU Polekh, N.M. AU Chernigovskaya, M.A. AU Yakovleva, O.E. PY 2019 IS 5 PB INFRA-M Academic Publishing LLC.