  A simple 'knee-like' approximation of the Lateral Distribution Function (LDF)
of Cherenkov light emitted by EAS (extensive air showers) in the atmosphere is
proposed for solving various tasks of data analysis in HiSCORE and other wide
angle ground-based experiments designed to detect gamma rays and cosmic rays
with the energy above tens of TeV. Simulation-based parametric analysis of
individual LDF curves revealed that on the radial distance 20-500 m the
5-parameter 'knee-like' approximation fits individual LDFs as well as the mean
LDF with a very good accuracy. In this paper we demonstrate the efficiency and
flexibility of the 'knee-like' LDF approximation for various primary particles
and shower parameters and the advantages of its application to suppressing
proton background and selecting primary gamma rays.
