PLASMA ROTATION IN TOROIDAL DEVICES WITH CIRCULAR CROSS-SECTIONS

The plasma rotation is theoretically investigated in toroidaI devices. The dependence of magnetic axis curvature and torsion on the longitud inal coordinate and magnetic field ripples are taken into account. The calculations are carried out within the large aspect ratio and circul ar magnetic surfaces approximation. General equations for the relaxati on of poloidal and toroidal velocities are obtained. The analysis of t hese equations is completed for the strongly collisional regime (the P firsch-Schluter regime). It is shown that, as a result of the relaxati on due to the ion parallel viscosity, there is an equilibrium with the ion toroidal velocity equal to zero. The general expression for the i on poloidal velocity in the Pfirsch-Schluter regime is obtained. As in the tokamak case, this velocity is proportional to the ion temperatur e gradient. It does not depend on the plasma density gradient and on t he radial electric field. The problems considered in the paper are of interest, specifically for toroidal devices of the ''Drakon'' (''Drago n'') kind [V. M. Glagolev et al., in Proceedings of the X European Con ference on Controlled Fusion and Plasma Physics, USSR, Moscow (Europea n Physical Society, Petit-Lancy, 1981), Vol. 1, p. E8]. (C) 1998 Ameri can Institute of Physics. [S1070-664X(98)01009-X]