Convection-dominated transport of solar cosmic rays

The Fokker-Planck equation for the transport of solar cosmic rays in interplanetary space, including the convection and energy-change terms as well as an absorbing boundary at finite distance from the sun, is solved for the exponential decay phase of solar particle events. The solution is applied to the case of low-energy (≈10 Mev) particles for which convection is important. Convective effects, particularly the relative constancy and energy-independency of the exponential decay time, previously noted in connection with the equilibrium anisotropy, appear explicitly in this solution.