Variations in the interplanetary magnetic field and some effects upon solar cosmic rays

The properties of the variations in the interplanetary field that were observed with the Mariner-2 magnetometer are employed in developing a model for the typical interplanetary field. Some properties of the behavior of solar protons in the model field are determined. It is shown that protons with energies less than 1 MeV would travel adiabatically throughout the solar system, protons with energies in the range 1–100 MeV would first encounter efficient scattering at heliocentric ranges beyond 1 a.u., protons with energies in the range 100 MeV–1 BeV would encounter efficient scattering at ranges near 1 a.u., and protons with energies greater than 1 BeV would first encounter efficient scattering at ranges less than 1 a.u. It is argued that various properties of solar-proton events may be accounted for by this model. However, non-relativistic solar-flare electrons would travel adiabatically throughout interplanetary space. Using the Mariner-2 data, it is shown that a good deal of the observed spread in the directions of travel of solar protons in the interplanetary field at the onset of an event is probably due to the variations in the orientation of the field rather than to a spread in particle pitch angles.