Two existing solutions for the diffusion of cosmic rays (CRs) are analyzed. The first one is a well-known solution in 3D over an infinite spatial domain and the second one is a 1D solution with an exponential decay initial profile over an infinite spatial domain. For each solution, the temporal evolution of the number of particles at a fixed distance has been analyzed. The anticorrelation between the flux of CRs and the magnetic field at one astronomical unit has been explained by adopting a careful choice of the astrophysical parameters involved.
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