Inductor orientation and ripple

Hi,  the honest answer is I am not entirely sure!  Finding that changing the orientation of the inductor has this effect is interesting but I haven't had chance to analyse all the components.  As you say, considering the traditional composite waveform approach, it appears the ESL component is inverted, but it also looks like the ESR component is inverted (this is most clearly seen in the slope of the on-time part of the wave form).  I suspect that this is not a change in ESL and ESR parasitic components of the output capacitors, but more likely additional parasitic elements due to coupling elsewhere in the layout.  As this layout is very small and tight, there are other potential paths for coupling such as the parasitic coil to coil capacitance of the inductor and other paths from switch node copper to other parts of the circuit.  There is a lot more investigation needed here!  Rgds  Jim