Corona discharge simulation is based on Nernst-Plank equations coupled with the Poisson's equation for electric potential. In unipolar model the corona sheath is not considered and usually one type of ions (positive or negative in correspondence with electrode polarity) is taken into account. In drift-diffusion approximation ionization processes in the corona sheath are computed and usually electrons, one type of negative and one type of positive ions are considered. It is revealed that models with one type of positive ions cannot reproduce experimental data if both current and ionic wind jet momentum are measured and compared with simulation. In this paper wire-wire geometry is considered.