  Io's movement relative to the plasma in Jupiter's magnetosphere creates
Alfv\'en waves propagating along the magnetic field lines which are partially
reflected along their path. These waves are the root cause for auroral
emission, which is subdivided into the Io Footprint (IFP), its tail and leading
spot. New observations of the Juno spacecraft by Mura et al. (2018) have shown
puzzling substructure of the footprint and its tail. In these observations, the
symmetry between the poleward and equatorward part of the footprint tail is
broken and the tail spots are alternatingly displaced. We show that the
location of these bright spots in the tail are consistent with Alfv\'en waves
reflected at the boundary of the Io torus and Jupiter's ionosphere. Then, we
investigate three different mechanisms to explain this phenomenon: (1) The Hall
effect in Io's ionosphere, (2) travel time differences of Alfv\'en waves
between Io's Jupiter facing and its opposing side and (3) asymmetries in Io's
atmosphere. For that, we use magnetohydrodynamic simulations within an
idealized geometry of the system. We use the Poynting flux near the Jovian
ionosphere as a proxy for the morphology of the generated footprint and its
tail. We find that the Hall effect is the most important mechanism under
consideration to break the symmetry causing the "Alternating Alfv\'en spot
street". The travel time differences contributes to enhance this effect. We
find no evidence that the inhomogeneities in Io's atmosphere contribute
significantly to the location or shape of the tail spots.
