Reduced Magnetohydrodynamic Equations in Toroidal Geometry

By applying a new assumption of density, i.e. R²ρ = const, the continuity equation is satisfied to the order of ε² with ε being the inverse aspect ratio. In the case of large aspect ratio, a set of reduced magnetohydrodynamic equations in toroidal geometry are obtained. The new assumption about the density is supported by the experimental observation in some extent.