kärnpotentialsfält

kärnpotentialsfält, or nuclear potential field, refers to the effective potential energy landscape experienced by nucleons (protons and neutrons) within an atomic nucleus. In quantum mechanical descriptions of the nucleus, each nucleon moves in a mean field generated by all other nucleons. The shape of this field determines the distribution of single‑particle energy levels and influences nuclear properties such as binding energies, shell structure, and collective excitations.

The concept was introduced to simplify the complex many‑body problem of the strong nuclear force. Instead of treating all pairwise interactions explicitly, the mean field approximation replaces them with a single effective potential. Classic forms used to model this field include the Woods–Saxon potential, which captures the finite range and surface diffuseness of the nuclear force, and the harmonic oscillator potential, which is convenient for analytic solutions and shell‑model calculations. Modern approaches often combine a central potential with spin‑orbit coupling and surface terms to reproduce experimental spectra accurately.

kärnpotentialsfält is central to several theoretical frameworks. In the independent‑particle model, nucleons occupy orbitals defined by the potential, forming nuclear shells analogous to electron shells in atoms. In mean‑field theories such as the Hartree‑Fock method, the potential is self‑consistently determined from the nucleon distribution. In collective models, the potential shape influences vibrational and rotational modes of the whole nucleus.

The study of nuclear potential fields remains active. Advances in ab initio methods and energy­density functionals aim to derive the mean field directly from underlying nucleon‑nucleon interactions, reducing reliance on phenomenological parameterizations. Understanding the nuclear potential field is therefore essential for describing nuclear structure, reactions, and astrophysical processes such as nucleosynthesis.