Gas ionization and current increase in a tokamak

The numerical simulation of the discharge development in a tokamak is carried out on the basis of onedimensional balance system of heat and particles. It is shown that the process of discharge formation is separated into two stages. During the first stage (its duration in the T-10 installation is 1-10ms) the neutral gas ionization takes place. During this stage monotoneous profiles of concentration, temperature and current density are produced. After the ionization the quick increase of the full current in a plasma is observed, which at the classic transfer coefficients should be accompanied by the intense current density and temperature skinning, not being observed in the real experiment. It is shown that with several resonance surfaces in the plasma its mixing, connected with the line of magnetic force reclosing, leads to the destruction of current density skinning distribution and current penetration into the plasma cord during the time, compared with the time of the current growth