  Self-assembly of particles with short-range attraction and long-range
repulsion (SALR) interactions on a flat and on a spherical surface is compared.
Molecular dynamics (MD) simulations are performed for the two systems having
the same area and the density optimal for formation of stripes of particles.
Structural characteristics, e.g. a cluster size distribution, a number of
defects and an orientational order parameter (OP), as well as the specific
heat, are obtained for a range of temperature. In both cases, the cluster size
distribution becomes bimodal and elongated clusters appear at the temperature
corresponding to the maximum of the specific heat. When the temperature
decreases, orientational ordering of the stripes takes place, and the number of
particles per cluster or stripe increases in both cases. However, only on the
flat surface the specific heat has another maximum at the temperature
corresponding to a rapid change of the OP. On the sphere, the crossover between
the isotropic and anisotropic structures occurs in a much broader temperature
interval, the orientational order is weaker, and occurs at significantly lower
temperature. At low temperature the stripes on the sphere form spirals, and the
defects resemble defects in the nematic phase of rods adsorbed at a sphere.
