A direct method for finding similarity reductions of partial differential equations is applied to a specific case of the Grad-Shafranov equation. As an illustration of the method, the frequently used Solov'ev equilibrium is derived. The method is employed to obtain a new family of exact analytical solutions, which contain both the classical and nonclassical group-invariant solutions of the GradShafranov equation and thus greatly extends the range of the available analytical solutions. All the group-invariant solutions based on the classical Lie symmetries are shown to be particular cases in the new family of solutions. © 2010 American Institute of Physics. ͓doi:10.1063/1.3456519͔The analysis of similarity reductions of partial differential equations plays an important role in many physical applications. Self-similar reductions not only solve problems with specific initial or boundary conditions 1 but also serve as intermediate asymptotic solutions to a much wider class of problems. 2 The classical method for finding a similarity reduction of a given partial differential equation is to use the Lie group method to determine a one-parameter group, admitted by the equation, and the corresponding group-invariant solution. 3 Recently White and Hazeltine 4 have used this approach to calculate the complete symmetry group admitted by the Grad-Shafranov equation 5,6 for the poloidal magnetic flux u͑r , z͒,in the particular case of constants F and G. The equation describes ideal magnetohydrodynamic tokamak equilibria in which both the pressure and the square of the poloidal electric current are linear functions of u͑r , z͒.Here and in what follows, the same notation as in Ref. 4 is adopted, although ͑r , z͒ is more often used in literature to denote the poloidal magnetic flux.White and Hazeltine 4 used the symmetry group to generate some new solutions from available solutions and derived three new group-invariant solutions to the GradShafranov equation. Not all interesting similarity reductions can be obtained using the standard Lie group method for finding group-invariant solutions. The well-known Solov'ev 7 equilibrium, for instance, is not among the Lie groupinvariant solutions to Eq. ͑1͒. A nonclassical method of group-invariant solutions 8,9 generalizes the classical Lie method by analyzing group transformations that do not necessarily map a given partial differential equation into itself. The nonclassical method can lead to additional similarity reductions.A direct method for finding similarity reductions was proposed by Clarkson and Kruskal. 10 The method is relatively simple to implement because it does not use group theory. The resulting similarity reductions, however, have been shown to be of both classical and nonclassical symmetry types. 11 The literature on exact solutions to the Grad-Shafranov equation is extensive. Exact solutions in terms of special functions have been derived for the case of a linear inhomogeneous equation, 12-15 and series expansion solutions to the homogeneous equation have been develope...