Air shower universality in the energy range of 1014 to 1022 eV

Universality in the development of air showers initiated by photons and the nuclei of cosmic rays is studied over a wide range of energies (10¹⁴–10²² eV). The scaling invariance of the lateral distribution of electrons and the universal relationship between a cascade’s age and radial scaling parameter (the root-meansquare radius of the electron component) are found to remain valid up to ultimate high energies with allowance for the Landau-Pomeranchuk-Migdal effect and interaction with the geomagnetic field. Possible applications of universality for matching, reanalyzing, and verifying the validity of data from different experiments, and for reducing the effect of the nuclear interaction model’s uncertainty on estimates of the mass composition of primary cosmic rays, are discussed.