Multichannel cosmic ray spectra and the large scale cosmic ray anisotropy can hardly be made compatible in the framework of conventional isotropic and homogeneous propagation models. These models also have problems explaining the longitude distribution and the radial emissivity gradient of the $\gamma$-ray Galactic interstellar emission. We argue here that accounting for a physically motivated correlation between the cosmic ray escape time and the spatially dependent magnetic turbulence power can naturally solve both problems. Indeed, by exploiting this correlation we find propagation models that fit a wide set of cosmic ray spectra, and consistently reproduce the cosmic ray anisotropy in the energy range ${10}^2–{10}^4\mathrm{GeV}$ and the $\gamma$-ray longitude distribution recently measured by Fermi-LAT.

• Received 8 March 2012

DOI:https://doi.org/10.1103/PhysRevLett.108.211102