On the one hand, the radiation is an important channel for the energy loss of the plasma, on the other hand many important plasma parameters can be determined from spectroscopic analysis of the emitted line radiation.
Examples are the flow velocity and the temperature of the ions, the density and temperature of the electrons, the concentration and production rate of impurities and the radial electric field. To this end, active and passive spectroscopy methods are used. The main areas of investigation are dedicated to the understanding of:
- erosion and transport of impurities
- transport of momentum and energy
- particle, momentum and energy flows in the divertor close to detachment
- radiation losses of the plasma within and outside of the last closed flux surface.