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Radial boundary layers in diffusing toroidal equilibria

Technical Report ·
DOI:https://doi.org/10.2172/7228548· OSTI ID:7228548

Analytic results in straight cylindrical geometry imply sharp density gradients near the boundary of a plasma decaying by classical diffusion. Utilizing an isothermal one-fluid magnetohydrodynamic model, we apply these results to toroidal configurations and obtain a set of nonlinear equations for a radial boundary layer. A dominant effect in this regime is convective plasma flow along magnetic lines of force, with velocity in the sonic range. This flow pattern matches onto the interior solution of Pfirsch-Schlueter convective flow. Solutions separable in the radial and poloidal directions are found that fulfill both boundary and periodicity conditions, and that result in both smooth subsonic poloidal flow, and weak shock transonic flows. Effects of the flow patterns on diffusion are discussed.

Research Organization:
Princeton Univ., NJ (USA). Plasma Physics Lab.
OSTI ID:
7228548
Report Number(s):
PPPL-1315
Country of Publication:
United States
Language:
English