The magnetic field generated around a single, spherical, neodymium magnet 5mm in diameter extends spherically into the atmosphere, and if another such magnet is then moved closer to the first they are attracted and come into contact, and obviously these two magnets will align N-S, and their external fields will combine as in diagram B below.
If more magnets are introduced linearly to these two they collectively form a N-S ‘wire-like’ magnet, and the combined longitudinal magnetic field extending into the atmospheric gases will be as in diagram C below, while the cross sectional, lateral field around this ‘wire’ will be as in diagram D below that.
Now if four such wires are constructed with the same N-S alignments and are brought together, the photo A below shows the collective structural alignments that are created, and in this structure the diversions of the magnets at each end mimic the alignments of iron filings around a standard magnet. And the image “Wires 2” depicts the observed magnetic alignments of these spherical magnets.
Of course the magnetic fields generated are acting continuously and extend invisibly into and through the atmosphere from the North and South poles of this structure to connect these poles.
In contrast however if four of these spherical magnets (which naturally connect linearly N-S) are placed together as depicted in diagram E below they form a stable structure and if similar structures are constructed and brought into contact laterally then they collectively form the linear ‘wire’ of spherical magnets, as in the photo B below, and the observed magnetic alignments of all these spheres are depicted in diagram F below this.
It is very important to note here that, unlike the N-S alignments shown in photo A, this collective arrangement of magnets does not extend any significant, e.g. measurable, magnetic fields externally into the atmosphere.
This structure is clearly replicated in the electron microscope image, G below, of the wire-like structure of gold atoms that are physically drawn out from a single microscopic gold particle.
Electron microscope image of copper atoms.
This suggests that the numerous, e.g. billions, of the atoms composing a macroscopic copper wire are naturally and ultimately aligned, and attracted, in the same way.
If a copper wire of tangible dimensions is attached to the positive and negative N-S poles of a 12 volt battery and a resistance is generated to the transmission of the current within the circuit, ultimately by means of the very fine wires of an electric bulb, from which some of the induced energy dissipates, is absorbed, into the atmosphere by means of the emission of radiant heat and light. Then a DC current is generated in the wire and the atoms of the wire align this field.
And if this DC current is reversed to S-N, then the magnetic moment generated by the battery will also realign the magnetic alignments of the copper atoms S-N in these wires as in the diagram below.
This reversal generates the 60 cycles/second alternating currents in general use worldwide.