Reciprocity (§5.6)
The physical consistencies of electric, magnetic and electromagnetic fields are (in gravimotion interpretation of Nature) crystal clear:
1. An electric field (§5.1) is graded activity.
2. A magnetic field also static electromagnetic field (§5.2) is oriented-activity.
3. And a dynamic electromagnetic field (§5.5) is whirling-activity.
Things get confusing when the effects of these fields on individual electrical particles such as electrons and protons are considered; because individual particles produce themselves side effects fields, which interfere and mingle with the primary fields.
Once I have brutally been kicked out of a science forum; the arbitrator listed me as persona non grata, forbidding me to sign in forever; all that because I expressed the idea that a field may act on a field. I should have given examples, such as the action of two magnets on each other, and the action of a gravitational field on light or electromagnetic fields, discovered by Einstein.

Now to get back to our subject, charged particles within any of the 3 fields above may create fields of their own interacting with the original fields in 3 different ways:
1. The interacting-particles are at rest with respect to any of the above fields. All "things" including the observer have precisely the same subjacent motions (
defined in §1.9
Considering the experiment is done on Earth, the subjacent motions are Earth's spin, Earth's rotational motion around the Sun, Sun's own motion within the milky way galaxy etc...
).
2. The interacting-particles are in a constant motion with respect to any of the above fields.
3. The interacting-particles are accelerated or decelerated within any of these fields.
Take the simplest combination 1 - A, described in §5.1; the situation is confusing because as soon as the interacting proton P or electron E starts moving, it also becomes first an accelerated particle turning the situation from A to C then that proton P own surrounding field (of type 1) turns into type 3 field! Yet much more different and complex situations may occur. One example of an even more complex situation is a moving magnetic field 2. Because moving an electromagnet is equivalent at increasing or decreasing the magnetic field surrounding it, it amounts at increasing or decreasing the electrical current that is at the origin of the field, the motion of a magnet makes that its own field is changed into a type 3 field, which is an electromagnetic field!
This is the reason one gets confused when one tries to understand Maxwell equations, which amazingly describes all of these complex situations in 4 net equations!
Maybe you noticed that Maxwell is one of my favorite physicists!