Spatially-resolved potential measurement with ion crystals

We present a method to measure potentials over an extended region using one-dimensional ion crystals in a radio frequency (RF) ion trap. The equilibrium spacings of the ions within the crystal allow the calculation of the external forces acting at each point. From this the overall potential is computed, and even potentials due to specific trap features can be determined. The method can be used to probe potentials near proximal objects in real time, and can be generalised to higher dimensions.