A lack of a strong dipole magnetic field.

They apply not only for a perfect dipole field, but also for fields that are approximately dipolar.

Actually, that should be inverse third power, not fourth, for the decay of a magnetic dipole field at long distances.

The dipole field is produced by a circular electric current flowing deep within the star, following Ampère's law.

In most cases we only consider an atom interacting with the electric dipole field of the photon.

There's not much of a field now, of course, but three billion years ago the magnetic dipole field was pretty healthy around here.

The solar dipole field, through similar processes, reverses again at the end of the 22-year cycle.

The Sun itself does not support long-term radiation belts, as it lacks a stable, global dipole field.

The main causes of this ordering are tensorial polarization forces and dipole fields.

This type of dipole field near sources is called an electromagnetic near-field.