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Ellipsoidal Coulomb Crystals in a Linear Radiofrequency Trap

U. Fröhlich·B. Roth·S. Schiller
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Abstract

A static quadrupole potential breaks the cylindrical symmetry of the effective potential of a linear rf trap. For a one-component fluid plasma at low temperature, the resulting equilibrium charge distribution is predicted to be an ellipsoid. We have produced laser-cooled Be$^+$ ellipsoidal ion crystals and found good agreement between their shapes and the cold fluid prediction. In two-species mixtures, containing Be$^+$ and sympathetically cooled ions of lower mass, a sufficiently strong static quadrupole potential produces a spatial separation of the species.

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U. Fröhlich, B. Roth, S. Schiller. 2004-12-09. Ellipsoidal Coulomb Crystals in a Linear Radiofrequency Trap. https://doi.org/10.1063/1.1976605

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