Fast current rise studied in the steady-state discharge of the Tuman-3 device

Mathematical simulation of experiments with rapid current rise ip=25 MA/s in the Tuman-3 tokamak is performed. It is shown that the time of current density stationary profile installation, which in the experiment is an order lower the skin time calculated for the whole cord is determined by the time of current pass through external region of plasma cord, where q>1. In the process of current rise on plasma periphery a developed magnetic island for the second mode is formed, as a result, thermal conductivity in the external part of the cord increases and periphery is not warmed up, therefore, the time of current penetration inside the cord decreases. Experimental data do not contradict neoclassical conductivity theory