Top – surfaces for the x, y, and z constant, showing the distribution of the current amplitude in the region around the current channel. The three surfaces intersect in a point close to the center of the current channel in Z direction. Also shown are the spine and fan field lines, together with the Z component of the magnetic field at the bottom of the simulation box. Bottom – distribution of the current density amplitude along three lines in X, Y, and Z direction. The lines intersect at the same point of intersection of the planes.