Recent simulations of the evolution of cosmic strings indicate the presence of small-scale structure on the strings. We show that wakes produced by such ‘‘wiggly’’ cosmic strings can result in the efficient formation of large-scale structure and large streaming velocities in the Universe without significantly affecting the microwave-background isotropy. We also argue that the motion of strings will lead to the generation of a primordial magnetic field. The most promising version of this scenario appears to be the one in which the Universe is dominated by light neutrinos.

• Received 7 March 1991

DOI:https://doi.org/10.1103/PhysRevLett.67.1057