  Here, we study radial solutions for first- and second-order stationary
Mean-Field Games (MFG) with congestion on $\mathbb{R}^d$. MFGs with congestion
model problems where the agents' motion is hampered in high-density regions.
The radial case, which is one of the simplest non one-dimensional MFG, is
relatively tractable. As we observe in this paper, the Fokker-Planck equation
is integrable with respect to one of the unknowns. Consequently, we obtain a
single equation substituting this solution into the Hamilton-Jacobi equation.
For the first-order case, we derive explicit formulas; for the elliptic case,
we study a variational formulation of the resulting equation. In both cases, we
use our approach to compute numerical approximations to the solutions of the
corresponding MFG systems.
