We present a numerical method for computing the pure-point spectrum
associated with the linear stability of multi-dimensional travelling fronts to
parabolic nonlinear systems. Our method is based on the Evans function shooting
approach. Transverse to the direction of propagation we project the spectral
equations onto a finite Fourier basis. This generates a large, linear,
one-dimensional system of equations for the longitudinal Fourier coefficients.
We construct the stable and unstable solution subspaces associated with the
longitudinal far-field zero boundary conditions, retaining only the information
required for matching, by integrating the Riccati equations associated with the
underlying Grassmannian manifolds. The Evans function is then the matching
condition measuring the linear dependence of the stable and unstable subspaces
and thus determines eigenvalues. As a model application, we study the stability
of two-dimensional wrinkled front solutions to a cubic autocatalysis model
system. We compare our shooting approach with the continuous orthogonalization
method of Humpherys and Zumbrun. We then also compare these with standard
projection methods that directly project the spectral problem onto a finite
multi-dimensional basis satisfying the boundary conditions.Comment: 23 pages, 9 figures (some in colour). v2: added details and other
changes to presentation after referees' comments, now 26 page