On 5/06/2018 1:51 PM, John Berry wrote: Actually, I have another one... Take a large loop apply a current, we see that each side of the loop experiences a pushing outwards.
Now, we remove one side, from the loop and replace it with capacitor plates. No we energize a current through our broken loop and each side feels a force pushing away from the center. But, we only have 3 sides now, the 4th side is a displacement current, and while the displacement current creates a magnetic field, on what is the force placed? It would seem that where the circuit completed through the electric permitivity of space, it would be space that is the charge carrier, maybe it is virtual particles being polarized? The point is that while this circuit will only produce thrust for a moment before we need to reverse our connections, we can do so and the directions all reverse except the direction of thrust which is the same. This is interesting as if you can put a current, if space can be polarized, then it can also be thrust against! Indeed I also thought about this situation at great length a long time ago, and even built a device which might have worked. However at the time I did not have an RF generator so tried to drive it by exciting the circuit with sparking. I did not see any effect and doing some calculations suggested that any effect that may be obtained with reasonable componentry will be negligibly small. How do you get even a fraction of an amp to flow through a capacitor with large spacing between the plates!? Only by using very high frequencies! And then you need the same very high frequency magnetic field to be generated 90 degrees out of phase with the displacement current passing through the capacitor to produce some force. A very difficult experiment that *might* achieve a negligibly small effect!