  The energy range encompassing the ankle of the cosmic ray energy spectrum
probably marks the exhaustion of the accelerating sources in our Galaxy, as
well as the end of the Galactic confinement. Furthermore, this is the region
where the extragalactic flux penetrates the interstellar medium and starts,
progressively, to be dominant. Although at lower energies it is likely that an
"average" population of supernova remnants can be defined to account for most
of the cosmic ray flux, this assumption is increasingly difficult to maintain
as higher energies are considered. One possibility is that supernovas are still
a main contributor along the first branch of the ankle region, but that the
acceleration is now coming from well localized regions with a characteristic
interstellar medium, or a sub-population of supernovas exploding in a peculiar
circumstellar environment. These possibilities are analyzed in the present work
using a two-dimensional diffusion model for cosmic ray propagation. Special
emphasis is given to the inner 200 pc of our Galaxy and to the spiral arm
structure in relation with the Sun position inside the disk.
