(right) Longitudinal projection of a hyperbolical Penning trap with cylindrical symmetry along the -axis. is the DC potential applied to the endcaps with respect to the ring. Due to the shape of the electrodes, the equipotential lines are hyperboloids of revolution. and give the characteristics dimensions of the Penning trap and are related by . (left) Equivalent circuit of the Penning trap with one stored ion. The ion can be described as an inductance () in series with a capacitor (). gathers all the capacitances between the trap electrodes or between the electrodes and ground. is the internal resistance of the power supply.
