Neoclassical rotation velocities in multispecies plasmas
- Oak Ridge National Lab., TN (United States)
- Univ. of Texas, Austin, TX (United States)
We examine the relationships between the poloidal, toroidal and parallel rotation velocities for typical plasma conditions in existing tokamak experiments. The radial force balance, neoclassical solution to the poloidal flow from the parallel force balance, and anomalous toroidal rotation axe included. A full multispecies formulation of the neoclassical transport theory is implemented in the NCLASS code (which includes arbitrary axisymmetric geometries and plasma collisionalities) to determine the poloidal rotation velocities. Comparisons are made with analytic relationships derived from a single impurity formulation of the problem. The roles of the radial electric field and species density and pressure gradients are evaluated. The determination of the radial electric field using the NCLASS solution for poloidal rotation and a local measurement of the toroidal rotation in conjunction with measured plasma profiles is discussed; it has been used in analysis of TFTR enhanced reverse shear plasmas. The ordering of banana orbit size small relative to local minor radius and gradients (as incorporated into initial versions of NCLASS) are examined for typical negative shear plasmas. We show the degree to which these constraints axe violated and demonstrate that finite orbit corrections axe required for better determination of the bootstrap current, particle fluxes and ion heat fluxes, i.e., the conditions r {much_lt} {Delta}{sub b} {much_lt} r{sub n}, r{sub T}, r{sub E} are significantly violated. Progress in relaxing these constraints is discussed.
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 489496
- Report Number(s):
- CONF-960354--
- Country of Publication:
- United States
- Language:
- English
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