Technically, you may be correct there.  Would you be satisfied if we described the wave form as sinusoidal, since all of the alternators we build fail to produce true faultless definitional sine waves to some degree or another.

But again, the purpose of the post was to refute the supposition that you would only get one hump, no electron flow in the other direction.  This clealy has an up (+) and a down (-).  In that limited sense, I think it looks pretty sine wavy to me.

Best regards,

In the first test, I compared two coils, one very small, and one medium (A and B respectively).  The traces for those two mini coils are shown in the second photo.  Coil A produced a big dead spot in the middle of the peak of the sine wave due to the magnet being over both legs at the same time and canceling the voltage.  Coil B wasn't so bad, but still a noticable dip.

Now, when I compared coils B and C, (medium and large, respectively) we see more intersting results.  Only the biggest coil has a nice full peak because there's very little overlap with the magnet covering both legs at the same time.  It's tempting to think that we should make great big holes in our coils.

That's not really true though, because a real coil has many turns, not just two.  So while part of two legs may be covered by the magnet, the additional copper you can pack in there still gives you more volts and amps out compared to the great big hole coil.  Up to a point anyway. Everything involves some compromise. So I wind coils with holes a little smaller than the magnet and cross my fingers.

Have a lovely day.