Do you understand particles of matter exist out ahead of the solar system in quantities less than in any vacuum artificially created on Earth? To think it is the particles which wave is absurd.
It is the aether which waves out ahead of the solar system.
Flags wave. People wave. But aether doesn't wave, except in your mind, where all the aether is. Waves in physics are nouns. The verb is propagate. They subtend space with energy. (Remember energy? You keep leaving it out, as if we're supposed to believe aether makes up for the deficit.) But waves propagate for the same reason fields propagate. And that reason is: they propagate without cause.
This gets to what "cause" means, but I'm only relating it in the context you're using, which is mechanics. (Your allusion to pressure, for example, while repudiating the Lorentz force which deflects a magnetic field when traversed by a charged particle). You want the universe to be made of dominoes of causation that topple one another ... from ... what? a Prime Mover?
... Energy (in this context) propagates, which is not mechanics. It's electromagnetics. Particles translate, which is mechanics. And this is why you can't connect the two. You have no perspective of EM at all. Energy is conserved, so the energy invested in accelerating a charged particle to a given velocity is equal to the radiant energy of its induced field.
Notice how this has nothing at all to do with aether?
When you say "physical" you evidently mean "mechanical". You seek a mechanical wave (as in acoustics), which is perhaps the basis of Newton's universe, but not Maxwell's. This was the same problematics with aether during that era that spanned their discoveries. They didn't yet have a sense of EM, so they kept searching for a nonexistent mechanical system--a medium. That's the same rationalizing that has you chasing "pressure", "displacement", "collision" (of clusters), "pushing" (of the heliosphere by radiant particles), and, of course, "waving"--and the mechanical interpretation of the double slit experiment, and even of gravity itself. These are all mechanical world views, narrow and highly oversimplified models obsoleted by EM.
The mechanical cause is far removed from the electromagnetic one. Mechanics (kinematics) invokes your personal sense of causality, because there is motion. There is before and after. The world of kinematics is one of space cut by time. Almost all the laws of mechanics derive from pinning mass to the space of this world, cut by time. (esp. the first and second derivatives). We don't generally think of dimensions as derivatives, but in this sense, the sense of "dimensions of existence", that's just about all we need to describe the mechanical world. (This, presumably, is your "physical" world.)
EM is another world. The object pinned to this world is not mass but charge. Added to the dimensionality of time-derivatives we find a special "dimension of existence" for the zeroth order case: electrostatics. Here is the magical property you seek through the nonsense of filling space with a superfluid. Electrostatics is the world of pure propagation. Before you can pretend to repeal Maxwell's laws and to replace them with "waving" mechanical aether, you have to answer Coulomb's Law, as a clue to what "causes" phenomena that you incorrectly interpret from the distorted lens of a mechanic.
In Coulomb's law, which is a dual for Newton's law of gravitation, there is no mechanical cause. The charge is ever-present. In Newton's Law, the mass is ever-present. "Ever-present" is, in the sense you mean it, "without cause." This why, when scientists and engineers tell you that the electrostatic force arises from the charges and distance between them, and that gravity arises from the masses and the distance between them, you simply scoff and post obnoxious and repetitive posts. You are seeking a cause in the mechanical sense. You want before and after.
What they are telling you, that you are completely shutting out, is that fields are persistent. A term you should learn is "attend". A moving charge is attended by a magnetic field. A static charge is attended by a static electric field. Mass is attended by a gravitational field. It's not a question of cause, as you think. It's a fact of simultaneity. To persist, to attend, simply means to exist conditionally, but not simply on account of cause.
That's putting the round peg of electromagnetics into the square hole of mechanics, the whole basis of your spurious beliefs.
