Synchronization Defects and Broken Symmetry in Spiral Waves

Spiral waves are investigated in oscillatory media exhibiting period-doubling bifurcations. In the period-doubled and chaotic regimes, the rotational symmetry of the spiral wave is broken. The loss of symmetry takes the form of synchronization defect lines where the phase of the local oscillation changes by multiples of $2\pi$. The internal structure and geometry of these synchronization defects is studied and a discussion of the possible types of defect lines is presented.