  This document contains refereed supplementary information for the paper
``Rapid planetesimal formation in turbulent circumstellar discs''. It contains
15 sections (\S1.1 -- \S1.15) that address a number of subjects related to the
main paper. We describe in detail the Poisson solver used to find the
self-potential of the solid particles, including a linear and a non-linear test
problem (\S1.3). Dissipative collisions remove energy from the motion of the
particles by collisional cooling (\S1.4), an effect that allows gravitational
collapse to occur in somewhat less massive discs (\S1.7). A resolution study of
the gravitational collapse of the boulders is presented in \S1.6. We find that
gravitational collapse can occur in progressively less massive discs as the
grid resolution is increased, likely due to the decreased smoothing of the
particle-mesh self-gravity solver with increasing resolution. In \S1.10 we show
that it is in good agreement with the Goldreich & Ward (1973) stability
analysis to form several-hundred-km-sized bodies, when the analysis is applied
to 5 AU and to regions of increased boulder column density. \S11 is devoted to
the measurement of random speeds and collision speeds between boulders. We find
good agreement between our measurements and analytical theory for the random
speeds, but the measured collision speeds are 3 times lower than expected from
analytical theory. Higher resolution studies, and an improved analytical theory
of collision speeds that takes into account epicyclic motion, will be needed to
determine whether collision speeds have converged. In \S1.12 we present models
with no magnetic fields. The boulder layer still exhibits strong clumping, due
to the streaming instability, if the global solids-to-gas ratio is increased by
a factor 3. Gravitational collapse occurs as readily as in magnetised discs.
