Position B: example of proton which exhibits a slow guiding centre drift. a) displays a zoomed view of the proton orbit (black), which begins at the location shown by a green orb, and ends at the location shown by a blue orb, with black trapezoids indicating the location of a change in sign of parallel velocity. The thin grey lines indicate locally interpolated B-field lines based on several orbit positions. The red isosurface denotes where the parallel electric field changes sign (E_|| = 0). Orbit properties for this proton are displayed in a) and c); b) shows the change in kinetic energy (KE) and parallel electric field component (E_||) as a function of time, while c) shows the normalised parallel velocity (v_||/ max(v_||)) and magnetic field strength (| B |) for this orbit.