Bootstrap current and neoclassical transport in tokamaks of arbitrary collisionality and aspect ratio
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
- Institute for Fusion Studies, The University of Texas, Austin, Texas 78712 (United States)
- Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)
A multi-species fluid model is described for the steady state parallel and radial force balance equations in axisymmetric tokamak plasmas. The bootstrap current, electrical resistivity, and particle and heat fluxes are evaluated in terms of the rotation velocities and friction and viscosity coefficients. A recent formulation of the neoclassical plasma viscosity for arbitrary shape and aspect ratio (including the unity aspect ratio limit), arbitrary collisionality, and orbit squeezing from strong radial electric fields is used to illustrate features of the model. The bootstrap current for the very low aspect ratio National Spherical Torus Experiment [J. Spitzer {ital et al.}, Fusion Technol. {bold 30}, 1337 (1996)] is compared with other models; the largest differences occur near the plasma edge from treatment of the collisional contributions. The effects of orbit squeezing on bootstrap current, thermal and particle transport, and poloidal rotation are illustrated for an enhanced reverse shear plasma in the Tokamak Fusion Test Reactor [D. Meade and the TFTR Group, {ital Plasma Physics and Controlled Nuclear Fusion Research}, 1990 (International Atomic Energy Agency, Vienna, 1991), Vol. I, p. 9]. Multiple charge states of impurities are incorporated using the reduced ion charge state formalism for computational efficiency. Because the force balance equations allow for inclusion of external momentum and heat sources and sinks they can be used for general plasma rotation studies while retaining the multi-species neoclassical effects. {copyright} {ital 1997 American Institute of Physics.}
- OSTI ID:
- 538469
- Journal Information:
- Physics of Plasmas, Vol. 4, Issue 9; Other Information: PBD: Sep 1997
- Country of Publication:
- United States
- Language:
- English
Similar Records
Neoclassical rotation velocities in multispecies plasmas
Bootstrap current for the edge pedestal plasma in a diverted tokamak geometry