Space- and Time-Resolved Study of Impurities in TFR Tokamak Plasmas

Space- and time-resolved profiles of impurity ions in TFR tokamak plasmas have been used in order to deduce diffusion velocities. ${\mathrm{O}}^{4+}$ ions, present in a peripheral plasma shell, have inward diffusion velocities of ∼2×${10}^3$ cm/sec, in agreement with theoretical values. ${\mathrm{Mo}}^{30+}$ ions, characteristic of the central hot plasma, have inward diffusion velocities of ∼ 10 cm/sec.