The Favourable Spatial Position Criterion

• FSP1: The time intervals corresponding to the INTERBALL TAIL PROBE (IB_TAIL) or GEOTAIL passage through the simulative magnetosphere boundary layer (BL).
• FSP2: That part of the FSP1 time intervals, which corresponds to the INTERBALL AURORAL PROBE (IB_AUR) or INTERBALL MAGION 5 (IB_MAG5) or POLAR passing through the cusp region, or diurnal (6 h < MLT < 18 h) auroral region & polar cap.
• FSP3: That part of the FSP1 or FSP2 time intervals, which corresponds to the magnetic conjugations between any couple of the considered spacecraft. The value of the relative geocentric angular distance between magnetic field line's footprints is considered during FSP3 situation selection. The mentioned angular distance value less then 5 deg is used as a criterion of the FSP3 situation. During magnetic mapping Tsyganenko 87 (Kp=2) + IGRF95 magnetic field models are used. The magnetic field line stop trace altitude (km) is 110.