Radiofrequency pseudopotential of a Paul trap ($U_{\mathrm{rf}}=Q^2|{\mathbf{E}}_{\mathrm{rf}}{|}^2/(4m{\Omega }_{\mathrm{rf}}^2)$)

When the radiofrequency drive is much faster than the Paul trap secular motion and Paul trap micromotion is small, averaging the oscillatory force produces the displayed effective potential. The electric field here is its peak oscillating amplitude. It is an energy, not a static electrostatic potential, so confinement does not contradict the static electrostatic no-trapping theorem. Excess Paul trap micromotion from displacement from the radiofrequency null is distinct from the intended slow Paul trap secular motion.