Sketch of the geometry used in the Line Current method. The auroral electrojets are represented by a series of line currents located at an altitude of 110 km. δB denotes the total magnetic residual, where δB_∥ is the component parallel to the main magnetic field and δB_⊥ is the perpendicular component. The triangle represents the satellite’s flight path, and the circles mark the positions of the line currents. (r_n, β_n) and (r_k, β_k) indicate the satellite and the line current at a given location, respectively. Δβ signifies a systematic shift toward lower latitudes in the location of the current maximum. Modified from Aakjær et al. (2016).