Many people have been using very confusing and sometimes contradictory language when describing electromagnetic fields and electromagnetic radiation. It's going to be hard to word this question so everyone understands so I'm going to use some examples.
I want to know if there is simply one large electromagnetic field that is affected by magnets, electricity, and electromagnetic radiation. If not, does that mean that each magnet, each electric flow, and each photon of electromagnetic radiation creates a separate electromagnetic field, all of which overlap but do not interfere with each other?
My understanding is that if electromagnetic fields or waves can interfere with each other, then they are really all just manipulations of one large electromagnetic field that fills all of space much like the Higgs field or spacetime does. In that understanding, would photons (electromagnetic waves) simply be waves in that field?
Here is an experiment example. Say I did a variation of the double-slit experiment. In this variation, instead of having one source that emits electromagnetic radiation from behind the two slits, there are two sources, one at each slit. In essence, I'm performing two single-slit experiments right next to each other projecting onto the same surface. Instead of firing only one photon at a time, each source fires a single photon at a time, both sources firing at the same time.
I have two predictions for what would happen. One for if there is one large electromagnetic field that fills all of space, and one for if each electromagnetic field is separate.
The top image is my prediction of what the result would look like if each field is separate, and by implication the waves do not interfere. The bottom image is my prediction if there is a single electromagnetic field and the waves in the field can interfere with each other.
I guess a good change in vocabulary could help. I imagine an "electromagnetic continuum" much like the spacetime continuum. In the spacetime continuum, a gravitational field would simply be a bending/warping of the spacetime continuum. In that sense, an electromagnetic field would be a "bending" or "warping" of the "electromagnetic continuum", and oscillations of the "electromagnetic continuum" would be electromagnetic waves/radiation.
A good way of phrasing my question with that use of vocabulary would be: "Does an electromagnetic continuum exist, or is it all just separate electromagnetic fields and oscillations?"
I hope these examples give enough information for you to understand my question(s) and correct any misconceptions I may have.