Solution of the three-dimensional nucleonic diffusion equation in the atmosphere

It is well known that the detailed knowledge of the propagation of cosmic rays in the atmosphere is indispensable to properly analyze cosmic ray data. From the mathematical point of view, the main problem is to solve the differential diffusion equation for the several cosmic ray components in the atmosphere, taking into account the energy loss of the particles in each collision at different depths. The authors solve the three-dimensional diffusion equation for the nucleonic cosmic ray component in the atmosphere, using a Feynman-like procedure of ordered exponential operators