TY JOUR TI Electron density in the polar F region ionosphere during solar minimum: modeling, radar and ionosonde observations KW Polar𝐹region ionosphere KW numerical modeling KW plasma density KW EISCAT radar KW SGOionosonde JO Russian Journal of Earth Sciences AU , .. AU , .. PY 2020 IS 20 PB ГСофизичСский Ρ†Π΅Π½Ρ‚Ρ€ Российской АкадСмии Наук