The influence of hydrogen influx toroidal inhomogeneity on the particle balance analysis in FT-1 tokamak experiments

In the study of particle and energy balance of a hot tokamak plasma, one must take into account the role of neutral hydrogen (deuterium), especially near the wall, where its density may be rather high, up to NH ∼ (1010 : 1011)cm -3. Being the source of charged particles, the atomic hydrogen at the same time due to the charge-exchange processes changes the ionization state of impurity ions, increasing strongly the radiation losses. These well known processes are used for energy dissipation in divertor volumes of large tokamaks.In FT-1 tokamak experiment (R=62.5 cm, a=15 cm) the role of poloidal limiters and gas puffing valve in particle recycling processes was studied. The measurement of radial and toroidal distribution of atomic hydrogen density was carried out by resonance fluorescence and passive spectral diagnostics. (author) 6 refs., 2 figs