To illustrate the contributions to the hyperfine field, one can hold a magnetometer in the middle of a carousel. The hyperfine field can be described with 3 terms.
– The dipole term can be seen as a child that is holding a bar magnet and is on the carousel but the carousel is still. You still measure a magnetic field at the center with the magnetometer.
– One can understand the contribution of the orbit term if you now replace the bar magnet of the child by a charged ball and let the carousel rotate. Then in the center of the carousel, you still measure a magnetic field due to the movement of the charged ball.
– The Fermi contact term can be seen as a child holding both the ball and bar magnet and is now moving on the carousel I think.