  We study a one-dimensional helical system with random Rashba spin-orbit
coupling. Using renor- malization group methods, we derive a consistent set of
flow equations governing the important con- trol parameters of the
backscattering process. Thereby, we prove the existence of disorder-induced
two-particle backscattering that can even be non-local in space. This analysis
allows us to derive the scaling form of the conductance at low temperatures. We
find that two-particle backscattering due to random spin-orbit coupling differs
from the one off a single Rashba impurity by both the scaling of the
conductance with the temperature and the relevance of the backscattering
operators.
