Resonance conditions and diffusion trajectories are developed for magnetospheric trapped particles interacting with whistler-type waves propagating along the magnetic field direction. The results are related to the plasma density and temperature. It is shown that finite temperature effects are insignificant for electrons interacting with right-handed whistler waves. For ions interacting with left-handed ion cyclotron waves the diffusion trajectories are found to deviate considerably from pure pitch angle diffusion for parallel energies less than the effective temperature. It is argued that pitch angle diffusion in the ring current is strongly inhibited at proton energies less than about 30 keV during strong storms and that an example of such behavior may have been observed by instruments aboard the S3 satellite. For electrons resonating with left-handed waves a minimum energy condition is derived, and wave growth rates are discussed for a beam of relativistic electrons injected into the magnetosphere. It is suggested that finite temperature effects could be invoked to modify the current theories of ring current precipitation.