multipolsernes

Multipolsernes is the Danish term for the multipoles, a concept used in physics and mathematics to describe the decomposition of a localized field into a hierarchy of components with increasing angular complexity. The idea provides a structured way to understand how a source distribution influences a field at a distance.

In electrostatics and magnetostatics, the potential of a localized charge or current distribution can be expanded as a multipole series. The leading term is the monopole, representing the total charge, followed by the dipole moment, quadrupole moment, octupole moment, and higher orders. Each term encodes a specific spatial pattern of the source distribution and its influence on the field.

The multipole expansion is particularly useful at large distances, where higher-order terms become small and the field can be approximated by a few leading components. It also aids the interpretation of molecular, atomic, and nuclear properties, such as how electron clouds create dipole or quadrupole moments and how these moments affect transitions and interactions.

Multipoles appear across many areas of physics and applied science, including atomic and molecular physics, antenna theory, gravitational physics, and crystallography. In magnetism, true magnetic monopoles have not been observed, so analyses often begin with dipole moments. The mathematical framework often employs spherical harmonics and tensor analysis to provide a convenient basis for representing the angular dependence of each multipole term.

See also: multipole expansion, spherical harmonics, dipole moment, quadrupole moment.