Effective ionization and emission rate coefficients of the helium atom in a plasma

Effective rate coefficients for ionization, line emission and line radiation power of the helium atom in an ionizing plasma are defined, with a collisional radiative model including new recommended excitation rate coefficients, which can be applied for divertor plasmas. Line intensity ratios for electron temperature and density measurements in this model are compared with results by Schweer et al. (J. Nucl. Mater. 196–198 (1992) 174–178) and the differences between the atomic data and the model are discussed.