Observations of 1.2‐ to 2.2‐ and 2.2‐ to 8.2‐Mev solar protons at low altitudes are studied with emphasis on the interaction zone between the stable trapping regions and the high‐latitude polar cap region. The data show: the appearance of anisotropic loss cone distribution, indicative of particle trapping, near the cutoff latitude on the dayside hemisphere only; the motion of the anisotropic region to lower invariant latitudes as the geomagnetic storm develops and the subsequent development of an isotropic loss cone distribution; and the movement of the solar proton distribution to stable trapping regions well within the ≥ 280‐kev electron trapping boundary. An explanation for these phenomena is offered in terms of cross‐Ldiffusion in the nightside hemisphere along with the development of some strong pitch angle diffusion process at all longitudes, which drives the ∼1‐Mev solar protons to isotropy in the loss cone. The development of strong pitch angle diffusion is strongly linked to the development of the symmetric ring current. This explanation may account for the relative inefficiency of direct solar proton injection as a source of trapped protons in spite of the fact that the solar protons have access to the stable trapping regions. Although the ∼1‐Mev proton lifetimes will be governed by the pitch angle diffusion process, it is important to note that the minimum pitch angle diffusion lifetime is of the order of or larger than ∼1‐Mev proton drift periods in the regionL≥ 4RE. These effects may also explain the longitudinal uniformity of PCA on the dayside hemisphere as well as some