Abundance modification by the diamagnetic effect

Abundances of elements with first ionization potential (FIP) less than 10 eV in the corona and solar wind are augmented relative to the solar photosphere. This enhancement has been found to be independent of both mass and charge. We emphasize two facts that are relevant to this problem: (1) Only elements with FIP < 10 eV are already ionized in the chromosphere, while in the corona, all elements are ionized. (2) It is known that diverging magnetic field structures anchored in the photosphere pass to the chromosphere (e.g., sunspots). Considering these facts, we construct a model in which the combination of the diamagnetic effect and gravity will pump charged particles, but not neutrals, from the chromosphere into the corona, thus producing the observed enhancement of low-versus high-FIP elements. This charged particle pump is operational irrespective of the existence of other mechanisms that have been proposed previously. Qualitative agreement is obtained with observed abundance ratios in the Sun and several stars.