A STUDY OF IMPURITY ROTATION BEHAVIOR IN THE TJ-I TOKAMAK

Poloidal and toroidal rotation velocities of impurity ions have been m easured with spatial resolution in the TJ-I tokamak from the shift of impurity lines. The behaviour of poloidal rotation with regard to plas ma density, plasma current and safety factor has been studied. Plasma core impurities rotate poloidally in the electron diamagnetic drift di rection, with a few exceptions, and with a different velocity for each species. In contrast intrinsic edge impurities may rotate in the oppo site direction for averaged densities below 1.5 x 10(13) cm-3. Whereas a central peaking impurity rotates poloidally like a rigid body, othe r species peaking at mid-radii exhibit sheared poloidal rotation. Thes e results have been related to changes in the plasma potential. The be haviour of impurity rotation in the TJ-I tokamak is discussed in the c ontext of the standard neoclassical theory.