Application of afxy-code for parameterization of ionization yield function Y in the atmosphere for primary cosmic ray protons

In this work is obtained new approximation for the yield function Y for cosmic ray induced ionization in the Earth atmosphere on the basis of simulated data. The parameterization is obtained using inverse nonlinear problem solution with afxy(analyze fx=y)-code. Short description of the methods is given. The found approximation is for primary proton nuclei, inclined up to 70 degrees zenith angle. This permits to estimate the direct ionization by primary cosmic rays explicitly. The parameterization is applicable to the entire atmosphere, from ground level to upper atmosphere. Several implications of the found parameterization are discussed.