The hyperfine field has three contributions:
-a spin dipolar contribution:
the electron around the nucleus can be thought of as a bar magnet, where the spin of the electron generates the magnetic field which stretches to the nucleus (the child).
-an orbital contribution:
the electron has an elementary charge -e, and can as such be thought of as a charged ball which orbits around the nucleus. As current is nothing more than moving charges, there will be a circular current (as if the charged ball is swung around the child by a carousel with its center at the child’s position) around the nucleus. This current induces a magnetic field, which can be felt by the child if he/she holds a magnetometer to measure the strength of the field.
-The Fermi contact contribution:
Not so easy to make an analogy for, but the electrons which are present in the nucleus (so at the child’s position) will give a by the magnetometer measurable magnetic field, but only if the amount of electrons in the nucleus with a spin up or down is different. We could say that the magnetometer will give a result different from zero only if the child holds a different amount of balls with 2 distinct colors.
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