The Telescope Array Experiment: An Overview aand Physics Aims

The Telescope Array (TA) experiment plans to deploy an array of 10 telescope stations in the west desert of Utah, USA and observes extremely high energy cosmic rays (EHECRs) by the atmospheric fluorescence. Its purpose is to study super-GZK (E > 10^20 eV) cosmic rays discovered by AGASA. In order to identify the origin of super-GZK events, TA has ~30 times larger aperture than AGASA and provides a particle identification by the shower profile measurement. The first step of construction will start as a hybrid detector with an AGASA/10 ground array and a part of fluorescence telescopes, which will unambiguously establish the existence of super-GZK and cluster events with much improved statistics and systematics. This paper describes the physics of TA and its overall planning