Fig. 3From: Relationship between large-scale ionospheric field-aligned currents and electron/ion precipitations: DMSP observationsa The orbit tracks of DMSP (black) and Swarm A (red), and the arrows indicate their flying dirction. b The 1Â Hz FAC signatures for the two satellites and c large-scale FACs by appling a low-pass filter with cut-off frequency of 20Â sBack to article page