  Energetic particles emitted by active stars are likely to propagate in
astrospheric magnetized plasma turbulent and disrupted by the prior passage of
energetic Coronal Mass Ejections (CMEs). We carried out test-particle
simulations of $\sim$ GeV protons produced at a variety of distances from the
M1Ve star AU~Microscopii by coronal flares or travelling shocks. Particles are
propagated within the large-scale quiescent three-dimensional magnetic field
and stellar wind reconstructed from measured magnetograms, and { within the
same stellar environment following passage of a $10^{36}$~erg kinetic energy
CME}. In both cases, magnetic fluctuations with an isotropic power spectrum are
overlayed onto the large scale stellar magnetic field and particle propagation
out to the two innnermost confirmed planets is examined. In the quiescent case,
the magnetic field concentrates the particles onto two regions near the
ecliptic plane. After the passage of the CME, the closed field lines remain
inflated and the re-shuffled magnetic field remains highly compressed,
shrinking the scattering mean free path of the particles. In the direction of
propagation of the CME-lobes the subsequent EP flux is suppressed. Even for a
CME front propagating out of the ecliptic plane, the EP flux along the
planetary orbits highly fluctuates and peaks at $\sim 2 -3$ orders of magnitude
higher than the average solar value at Earth, both in the quiescent and the
post-CME cases.
