I see those donuts on a rope contrails daily.
If I would take a pic of the sky at any moment you'll see an odd trail.
Holland is one of the busiest skies in europe.
I actually saw contrails that looked excactly like the famous donut on a rope pic, many times this year.

Ok.. Well i didnīt really suspect that the aurora was flying over my house... And it was awfully quiet..

If the aurora had pulse detonation engines you would not be able to see the rings. In a pulse detonation engine the engines have to fire several times a second so the smoke trail would be constant. The donut on a rope contrails look like a pulse detonation engine that is firing about once a second. Way to slow.