Effective charge of a plasma in tokamak with graphite wall and graphite limiter (TM-G)

Several methods were used to evaluate a value of effective plasma charge Zeff in tokamak with the first wall completely made of graphite and graphite diaphragm (TM-G). Also injection of a small carbon quality to plasma on laser irradiation of the graphite wall was used alongside with traditional methods (using plasma conductivity and intensity of bremsstrahlung in the visible region). As carbon was practically the only impurity in hydrogen plasma TM-G (oxygen ion concentration was tens times lower than carbon ion concentration, the rest impurities was not detected spectrally), time and amplitude characteristics of additional line intensity CV and soft X radiation appearing at that were used for C+5 and C+6 ion concentration calculation on the discharge axis as well as factor of exceeding plasma X radiation intensity. For discharges with electron temperature of up to 900 eV on filament axis and value of mean plasma density up to 7x1013 cm-3 all the methods give values of effective plasma charge not exceeding 1.5