  We study the formation of stripe order within the SO(5) theory of high T_c
superconductivity. We show that spin and charge modulations arise as a result
of the competition between a local tendency to phase separate and the
long-range Coulomb interaction. This frustrated phase separation leads to
hole-rich and hole-poor regions which are respectively superconducting and
antiferromagnetic. A rich variety of microstructures ranging from droplet and
striped to inverted-droplet phases are stabilized, depending on the charge
carrier concentration. We show that the SO(5) energy functional favors
non-topological stripes.
