| Popis: |
While developing and investigating the control system of the plasma position and current in a tokamak, the main tasks are as follows: - the main mode calculation of the supply system of the poloidal field coils; - the investigation of plasma motion stability. The first task can be solved by means of a magnetostatic code.It is preferable to use the dynamic mode calculation, which allows to determine the “equilibrium” currents and voltages of the poloidal field coils, the induced current loops being taken into account as well. In the report, the calculation technique, applied to investigate the T-15 plasma position control system, is discussed. Similar calculations have been accomplished for the steep-type torus “Tuman-3”. The calculation results are compared with the experimental data, obtained for the ohmic heating tokamak operation. In an iron-core tokamak (especially when the aspect ratio is less than 3) the effect of plasma attraction to the core changes greatly the horizontal motion picture. In the report the criteria of the horizontal and vertical motion stability. The investigation results of the plasma motion stability in T-15 and “Tuman-3” are also presented. The operation conditions of “Tuman-3” at the discharge start, when the inductor current is near zero and the magnetic flux is “frozen” by the chamber current are discussed in detail. The experimental data of the plasma position control system for “Tuman-3” are given. |
