re:Significant nuances or trivia.
You said:
IE, if we know the strength and configuration of the magnetic field, we should be able to determine the strength and configuration of the underlying electric currents?
TRUE, according to my understanding of electronics.
You said:
"Electric current can be directly measured with a galvanometer, but this method involves breaking the circuit, which is sometimes inconvenient.
Not only inconvenient but I would say impossible in situations such as in the case of the permanent magnets.
If such a miracle could be accomplished then we could get constant current out of a permanent magnet without any input power. ;-)
You said:
"Current can also be measured without breaking the circuit by detecting the magnetic field associated with the current."
IE, magnetic fields are diagnostic for electric currents. Where we see one, we can infer the other?
I believe that to be true.
In permanent magnets the “current†is intrinsic to the atomic structure.
You said:
"Conventional current" follows the direction of positive charges in a circuit by convention. "Electron current" or "electron flow" follows the direction of negative charges in a circuit (generally considered to be the opposite of the direction of "conventional current"). "Bidirectional flow" is a current with positive charges flowing one way and negative charges flowing the other in the same circuit (since the opposite charges will be accelerated in opposite direction in the same electric field / potential; yes?).
YES. When electroplating was discovered sometime in the eighteen hundreds, it was noticed that the metal in the electrolyte seemed to flow from the positive towards the negative polarity of the electrodes, since it was the negative plate that was coated with the “plated†metal.
Thus the word “current†for the flow of electricity.
The word “current†was used to imply the quantity or volume of flow per unit of time.
The experiments with vacuum tubes proved that within the glass tubes there was no flow or “current†in the same manner as in electroplating, but there was a flow of electrons from the negative towards the positive polarity.
Later experiments proved that positive ions moved towards the negative potential and the negative electrons moved towards the positive potential.
But theses explanations do not shed any light on the nature of magnetic fields.
There are several theories as to how, and why the magnetic fields are associated with moving electrons.
Naturally my theory is the best. ;-)
Unfortunately I can not explain it here because ARRhELL will simply convert the discourse into a useless flame war.