EQUATORIAL STRING LOOPS IN VAIDYA-PAPAPETROU SPACETIME

We examine the motion of test equatorial string loops in a self-similar Vaidya-Papapetrou spacetime. We obtain different qualitative behaviors for values of the power parameter λ above and below the critical value λc=1/8. For λ<λc strings can nucleate at the singularity and propagate outwards to a maximum radius, after which they recollapse. The collapsing behavior is universal (i.e., λ-independent), whereas the nucleation critical exponents are λ dependent. © 1995 The American Physical Society.