Calculation ofZ eff from plasma resistivity in IR-T1 tokamak

The effective ion charge,Z eff, represents the average charge of ionsZ i of gasses inside the system, which indicates the level of the impurities in the plasma. Several techniques have been applied to estimateZ eff, like mass spectroscopy, anomaly factor and Bremsstrahlung radiation. We estimatedZ eff in the IR-T1 tokamak through anomaly factor. The IR-T1 tokamak is a small air-core transformer tokamak with circular cross section and with out conducting shell and divertor. Its aspect ratio is $$\frac{R}{a} = \frac{{45 cm}}{{12.5 cm}}.$$ For a tokamak discharge of 30 kA plasma current and 1.5 V of loop voltage and by anomaly factor we observed thatZ eff value is about 1.5.