A dipole is simply a separation of charges . Dipoles are formed when unlike charges are separated. The natural attraction of opposite charges and the repulsion of like charges generate electrical currents in the body. The body and its parts are 3 dimensional structures and thus have volume. When a dipole is formed, current flows until isopotentiality is reached, if nothing serves to maintain the separation of charges.
Solid angles are important in measuring the amplitude of dipoles.
The amplitude of a dipole as measured by an electrode is proportional to the solid angle it presents to the electrode and the actual voltage difference between the poles. Conversely, the closer an object is, the larger the apparent size presented to the observer. A hypothetical dipole, shown here as a disk, in a volume conductor. The charges have been separated so that the upper side of the disk is negative, the lower side positive. Note that the voltages measured by the electrodes would differ from one another because the angles are different, even though the cross-sectional area of the dipole is the same.