Gravitational back-reaction near cosmic string kinks and cusps
  We find the leading-order effect of gravitational back-reaction on cosmic
strings for points near kinks and cusps. Near a kink, the effect diverges as
the inverse cube root of the distance to the kink, and acts in a direction
transverse to the worldsheet. Over time the kink is rounded off, but only
regions fairly close to the kink are significantly affected. Near cusps, the
effect diverges inverse linearly with the distance to the cusp, and acts
against the direction of the cusp motion. This results in a fractional loss of
string energy that diverges logarithmically with the distance of closest
approach to the cusp.
