TY JOUR TI Position of the main ionospheric trough polar wall in magnetically quiet conditions according to data from the ionospheric Tixie Bay station and DMSP satellites KW ionosonde KW meridional chain KW main ionospheric trough KW polar wall KW magnetically quiet conditions KW contracted oval KW electron density JO Solar-Terrestrial Physics AU Stepanov, A.E. AU Khalipov, V.L. PY 2025 IS 11 PB Institute of Solar-Terrestrial Physics SB RAS