ON THE RELATION BETWEEN RADIATION LEVEL, CENTRAL IMPURITY CONCENTRATION AND HELIUM EXHAUST IN A BURNING FUSION PLASMA

For a stationary burning fusion plasma a relation is derived and discu ssed which describes the close link between energy confinement, He-exh aust efficiency, central impurity density and the corresponding radiat ion level from impurities at the plasma boundary. Such a coherent appr oach helps to identify crucial parameters. Possibilities for further o ptimization are deduced from scalings of the radiation level with resp ect to the electron density, transport coefficients, impurity charge Z and He-exhaust efficiency.