Contribution of Quantitative Spectroscopy to Fusion Plasma Research

In fusion plasmas, different roles are required for impurities in terms of atomic number, Z; in low temperature peripheral (divertor) plasmas, enhancement of low Z impurity radiation is of importance for mitigating plasma heat load onto plasma-facing walls, while in high temperature core plasmas, suppression of impurity radiation, particularly by high Z impurity ions, is essential for maintaining high temperature. This talk discusses a mechanism, which enhances low Z impurity radiation in divertor plasmas and a method available for validating ionization and recombination rates of high Z impurity, tungsten (W) based on quantitative spectroscopy.