Unusual Time Structure of Extensive Air Showers at Energies Exceeding 1017 eV

Abstract

Extensive air showers characterized by a multicomponent time structure were detected at the experimental Horizon-T array deployed at the Tien Shan High-Altitude Science Station of Lebedev Physical Institute, Russian Academy of Sciences, at an altitude of 3346 meters above sea level. Such a structure manifested itself in showers of energy above 10¹⁷ eV and suggests that, in contrast to the standard mechanism of the development of a nuclear-electromagnetic cascade, shower particles reach the observation level as components of several shower disks.