and with the turbulence strength; for instance, in 3D isotropic turbulence $\kappa_\perp^{D}$ scales as $\kappa_\perp^{D} \propto (\sigma r_g)^2$ [@Fraschetti.Jokipii:11], leading to a steep scaling with respect to the unperturbed field $\kappa_\perp^{D} \propto B_0^{-2}$, as $\sigma^2$ is approximately uniform. T Tauri stars harbor kilogauss surface-averaged magnetic fields [e.g. @Johns-Krull:07], three orders of magnitude greater than the present day Sun. The aforementioned scaling of $\kappa_\perp^{D}$ with $B_0$ hampers the transport of EPs in the perpendicular direction within the circumstellar ambient medium of a T Tauri star with respect to the Sun. Thus, close to the T Tauri star the departure of EPs from field lines is expected to be very small whereas at larger distances EPs are more and more unleashed from the magnetic field.

For a solar wind proton with a kinetic energy of a few GeV measured [*in situ*]{} at $1$ AU, and for a Parker spiral field $B_0 = 5 \times 10^{-5}$ G, the gyroradius is $r_g \sim 10^6$ km; such a gyroscale shrinks down to $ \sim 10^2$ km at a distance less than $10 R_{\star}$ from the T Tauri star that we consider in our simulations. Therefore, $r_g$ is resonant with much smaller turbulent scales than in 