Spatial distribution of protons from neutron decay trapped by the geomagnetic field

The neutron sources at the earth due to galactic cosmic rays and solar protons interacting with the terrestrial atmosphere and also due to solar neutrons are examined quantitatively to see if the observed radiation belt protons can be produced by these neutrons. It is shown that solar protons and solar neutrons do not play any important part in producing the trapped protons. It seems that galactic cosmic rays may be able to make the observed high energy inner-belt proton flux near the equator, but it is difficult to see how the fluxes off-equator can be produced without some other mechanism being involved. Also forE ≤ 10 Mev the galactic cosmic-ray source is inadequate to produce the observed fluxes even for the center of the inner belt.