In the outer heliosphere, beyond the solar wind termination shock, it is
expected that the warped heliospheric current sheet forms a region of closelypacked,
multiple, thin current sheets. Such a system may be subject to the
ion-kinetic tearing instability, and hence generate magnetic islands and hot populations
of ions associated with magnetic reconnection. Reconnection processes
in this environment have important implications for local particle transport, and
for particle acceleration at reconnection sites and in turbulence. We study this
complex environment by means of three-dimensional hybrid simulations over long
time scales, in order to capture the evolution from linear growth of the tearing
instability to a fully developed turbulent state at late times. The final state develops
from the highly ordered initial state via both forward and inverse cascades.
Component and spectral anisotropy in the magnetic fluctuations is present when
a guide field is included. The inclusion of a population of new-born interstellar
pickup protons does not strongly affect these results. Finally, we conclude that
reconnection between multiple current sheets can act as an important source
of turbulence in the outer heliosphere, with implications for energetic particle
acceleration and propagation.