Energetic ion phase space density profiles are strikingly similar in the inner magnetospheres of Earth, Jupiter, and Saturn for ions of first adiabatic invariant near 100 MeV/G and small mirror latitudes. Losses occur inside L≈7 for Jupiter and Saturn and inside L≈5 at Earth. At these L values there exist steep plasma density gradients at all three planets, associated with the Io plasma torus at Jupiter, the Rhea-Dione-Tethys torus at Saturn, and the plasmasphere at Earth. Measurements of ion flux tube contents at Jupiter and Saturn by the low-energy charged particle experiment show that these are similar (for oxygen ions 5 ≲ L ≲ 9) to those at earth (protons 2 ≲ L ≲6). Furthermore, the thermal ion flux tube contents from Voyager plasma science data at Jupiter and Saturn are also very nearly equal, and again similar to those at Earth, differing by less than a factor of 3 at the respective L values. The near equality of energetic and thermal ion flux tube contents at Earth, Jupiter, and Saturn suggests the possibility of strong physical analogies in the interaction between plasma and energetic particles at the plasma torii/plasma sheets of Jupiter and Saturn and the plasmasphere of Earth.