Cosmic rays from the knee to the ankle

The shape and composition of the primary spectrum as well as the large-scale anisotropy in the arrival direction of cosmic rays are key elements to understand the origin, acceleration and propagation of the Galactic radiation. Besides the well-known knee and ankle features, the measured energy spectrum exhibits also a less pronounced but still clear deviation from a single power law between the knee and the ankle, with a spectral hardening at $\sim 2\times {10}^{16}\text{eV}$ and a steepening at $\sim {10}^{17}\text{eV}$. The average mass composition gets heavier after the knee till $\sim {10}^{17}\text{eV}$, where a bending of the heavy component is observed. An indication of a hardening of the light component just above ${10}^{17}\text{eV}$ has been measured as well. First indications of anisotropy of the arrival direction in the southern hemisphere have been reported at $\sim {10}^{15}\text{eV}$.