A Z-pinch capable of moving objects of that mass at those speeds all by itself would also necessarily produce movements along a z-axis that moved entire stars down it's length, and continued to do so.
And every galaxy is continuing to move through space, in the z direction relative to the magnetic field, or along the Birkeland current pathways.
If however the movements are primarily caused by gravity, we'd expect to observe nice little elliptical orbits, that can form at various angles, exactly the way we see near the core of our own galaxy.
Sort of like atoms, where gravity controls them? Or do orbits at various angles not require that for an explanation?
Exactly what we would observe if the electric current input was also not constant, elliptical orbits instead of circular.
Charged Particle in a Magnetic Field
There IS gravity involved. The plasma mass in the center of our galaxy behaves the same way as the plasma mass that is our sun, and likely has the exact some composition of an inner solid body. But it is the Birkeland Currents that give the galaxy its spiral momentum, shape and formation, also it's movement through space. Every orbit IS a spiral, even the earth. As it orbits the sun, the sun orbits the galaxy, so in reality that orbit is a spiral. Don't limit yourself to x and y when thinking of the earth orbiting the sun. The sun is not sitting still, nor is the galaxy. If there was no spiral, the earth would be left behind as the sun moved on. And all the stars would be left behind as the galaxy moved on.
I contend the stars are ejected from that central body and then eventually enter stable orbits, although some have yet to do so, hence what we call rogue stars. As planets are ejected from stars and enter into stable orbits. Hence our myths of gods being born, having no existence before and then slowly fading from the scene as they cooled and moved into their orbits as we see them today.
I'd say the movements of the stars themselves look to be more consistent with a heavy gravitational object in the core of the galaxy rather than just due to movement inside of a z-pinched thread of plasma. IMO that rotating heavy object acts to anchor the flow of current through the galaxy, and it becomes the focal point of electrical energy flowing through the galaxy.
And just what IS gravity? The balance of the electrical and magnetic forces when matter is in close confines?
And I contend that that heavy object was created by the flow of current. That the Birkeland Currents pinched the surrounding plasma matter in, plasma clearly visible that they block out in their orbiting star simulations.
http://i989.photobucket.com/albums/af16/sjw40364a/galacticring_zpsa63c625a.jpg
That mass which when the electrical stress becomes too great fissions, and the quasar is born, which slowly evolves into the galaxy we know. From quasar to BLac to proto-galaxy and finally a galaxy in it's own right.
ALL supernova when studied clearly turn out to be binary systems. I contend this is because the electrical stress becomes too great and they fission and become that binary system. Just as galaxies do and form quasars. (see the fissioning section in the link below)
Stellar evolution in the electric universe
You may indeed however have a very good point related to electrical oscillations being a factor rather than trying to explain the whole thing from rotation alone. That is an *excellent* possibility IMO.
And I certainly do not claim gravity is not involved, whatever that is. Just another manifestation of the EM force IMO, when they are balanced. And I am certainly not arguing something big and heavy is not in the center of our galaxy, it is quite clear there is, but it is there because that is where the pinch is located. Do pinches in lab experiments with plasma require an anchor object? Or would the compression of the surrounding matter cause the anchor object, which then contributes to the parameters? IMO opinion it is the latter. The pinch forms the object, which then contributes to the overall behavior we observe.