For a surface current equilibrium model of an axisymmetric, toroidal main plasma surrounded by a pressureless tenuous plasma with force-free fields, the structure of the force-free magnetic fields is investigated by using analytical solutions of the Helmholtz equation in toroidal coordinates and employing a Fourier decomposition. The calculation is performed without the approximation of an expansion with respect to the inverse aspect ratio. The poloidal beta βp, and the aspect ratio of the inner main plasma, Rp/γp=cosh σp, are chosen to be characteristic of a high-β tokamak. The force-free fields satisfy the relation j×B=0 or ∇×B=αB, where α 3s assumed a constant in space.
For the fixed value of α, the stagnation point approaches the main plasma surface as βp, β and safety factor q increase. For the fixed values of βp, β and q, the stagnation point departs far from the plasma surface as α decreases. Therefore, it is possible to fix the stagnation point spatially by decreasing α even if the, values of βp, β and q increase.
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