Progress on air shower observations with the SKA

Construction of low frequency component (50 - 350 MHz) of the Square Kilometre Array has started in Australia. With an immensely dense core of almost 60 thousand antennas within a square kilometer, the telescope provides a unique opportunity to study cosmic rays in the energy range between the knee and the ankle. High resolution observations and new analysis strategies will provide more insight into the most powerful Galactic accelerators, and the onset of the extragalactic component. An array of radio-quiet particle detectors will be deployed at the SKA-Low core for the purpose of triggering. A small prototype array has recently been installed at the Murchison Widefield Array, and an upgraded design is currently being developed. The capabilities of the SKA are explored with state-of-the-art simulation codes like CoREAS, and the new template synthesis technique, that provides a huge gain in computation speed, which is indispensable for next-generation observatories like the SKA. Using standard techniques, it is demonstrated that the SKA will achieve a reconstruction resolution on Xmax of 6 to 8 g/cm$^2$. However, the combination of dense ground coverage and large bandwidth allows for the development of new analysis strategies that provide additional insight in the characteristics of the primary particle and the physic in the air shower. Reconstruction of the shape of the longitudinal development and the identification of double-bump showers will put new constraints on both the mass composition and the hadronic interactions. The SKA will be able to reconstruct showers down to energies of 10 PeV or even 1 PeV with beamforming techniques. This expands the energy range over which mass composition analysis can be performed and might even allow to observe PeV gamma-rays, if an efficient photon/hadron separation is possible.