We discuss the capability of '100 GeV' class imaging atmospheric Cherenkov telescope (IACT) arrays as future powerful instruments of ground-based gamma-ray astronomy. It is assumed that the array is gathered from individually triggered quadrangular 4-IACT 'cells' with a linear size of about 100 m. The multi-cell concept allows coverage of large detection areas economically, and at the same time the effective exploitation of the stereoscopic approach of determination of the shower parameters using information obtained by several IACTs simultaneously. Determination of arrival directions of gamma-ray primaries on an event-by-event basis with accuracy delta theta less than or equal to 0.1 degrees combined with high suppression efficiency (at both the hardware and software levels) of the background hadronic showers by a factor of approximate to 10(3), and large, up to 1 km(2) collection areas, can provide minimum detectable energy fluxes of greater than or equal to 100 GeV gamma-rays from point sources down to 10(-13) erg/cm(2) s which is about 3 orders of magnitude lower than the current sensitivities achieved by the satellite-borne detectors at MeV and GeV energies. High sensitivities of multi-IACT arrays would partially compensate the limited efficiency of the technique for all-sky surveys, as well as allow study of moderately extended (less than or equal to 1 degrees) gamma-ray sources. IACT arrays with minimum detectable fluence of greater than or equal to 100 GeV gamma-rays S-gamma erg/cm(2) are well suited for effective exploration of highly sporadic nonthermal phenomena from different classes of astrophysical objects on time-scales from less than or equal to 1 s to several minutes. (C) 1997 Elsevier Science B.V.
