The coupling between the protonosphere and the normalFregion

The proton distribution in the upper portion of the F2 region must follow a chemical equilibrium distribution up to a critical level, hc, which is determined by the condition λΛ = H2, where Λ is the mean free path for the scattering of protons by oxygen ions, A is the charge-exchange mean free path for protons among oxygen atoms, and H is the scale height of atomic oxygen. Above this critical level, the distribution of protons is governed by diffusion. The number of protons in the whistler medium (that is, the protonosphere) is large enough, and the rate of diffusion of protons through oxygen ions slow enough, so that no large diurnal changes in whistler-region ion concentrations can be expected. This is in agreement with observation. The weak coupling between the oxygen ions in the normal F2 region and the protons in the protonosphere lends support to the position that the protonosphere should be considered separately from the heavy ion region which constitutes the normal ionosphere; the protonosphere can be thought of, in large degree, as floating on top of the normal ionosphere.