  We show that the complex shape of the cosmic ray (CR) spectrum, as recently
measured by PAMELA and inferred from Fermi-LAT gamma-ray observations of
molecular clouds in the Gould belt, can be naturally understood in terms of
basic plasma astrophysics phenomena. A break from a harder to a softer spectrum
at blue rigidity R\simeq 10 GV follows from a transition from transport
dominated by advection of particles with Alfven waves to a regime where
diffusion in the turbulence generated by the same CRs is dominant. A second
break at R\simeq 200 GV happens when the diffusive propagation is no longer
determined by the self-generated turbulence, but rather by the cascading of
externally generated turbulence (for instance due to supernova (SN) bubbles)
from large spatial scales to smaller scales where CRs can resonate.
Implications of this scenario for the cosmic ray spectrum, grammage and
anisotropy are discussed.
