1 EX / P 4 - 15 Overview of Experimental Studies on IR - T 1 Tokamak

An overview of experimental studies on IR-T1 tokamak is presented. Several issues of plasma displacement measurement are investigated. An analytic solution of the Biot–Savart law, which is used to calculate magnetic fields created by toroidal plasma current, is presented. Results of calculations are compared with the experimental data obtained in no-plasma shots with a toroidal current-carrying coil positioned inside the vessel to simulate the plasma movements. The results show a good linear behavior of plasma position measurements. An array of Mirnov coils employed for measurement of plasma position, too. The results show that Mirnov array can not be used for this measurement without concerning high field side errors. An external resonant helical magnetic field (RHF) applied to plasma. The aim of these experiments was to understand the effect of RHF on light impurities radiation and horizontal displacement measurements. Measurements results of visible line emissions of O, C impurities and Hα radiation with and without RHF (L=2) show that the addition of a relatively small amount of resonant magnetic helical field (L=2 & L=3) could be effective for improving the quality of the discharge by reducing of light impurities radiation. The effect of RHF in plasma displacement measurement shown an increase in flux value about %5 for L=2, L=3 separately and about %10 for L=2&3 when apply together. In other experiments, Studies of plasma interaction with titanium coated ferritic steel have been performed. Depth of impurity penetration and retention, and the surface roughness were measured using surface analysis methods. The results show that titanium acts as an effective getter for oxygen but its fast erosion poses a problem. A change in roughness with respect to position of samples has been observed.