Schematic representation of the computational domain used in this study. The direction of the assumed magnetic field is indicated by B, while the HP is located at x = 0, separating heliospheric (the shaded region where x< 0) and interstellar (where x> 0) regions, i.e. separating the inner and outer heliosheath. In this simulation, heliospheric particles originate at all red coloured boundaries, while blue boundaries indicate the source of galactic particles. The length unit is 1 AU.