  The intracluster medium of galaxy clusters is an extremely hot and diffuse,
nearly collisionless plasma, which hosts dynamically important magnetic fields
of $\sim \mu {\rm G}$ strength. Seed magnetic fields of much weaker strength of
astrophysical or primordial origin can be present in the intracluster medium.
In collisional plasmas, which can be approximated in the magneto-hydrodynamical
(MHD) limit, the turbulent dynamo mechanism can amplify weak seed fields to
strong dynamical levels efficiently by converting turbulent kinetic energy into
magnetic energy. However, the viability of this mechanism in weakly collisional
or completely collisionless plasma is much less understood. In this study, we
explore the properties of the collisionless turbulent dynamo by using
three-dimensional hybrid-kinetic particle-in-cell simulations. We explore the
properties of the collisionless turbulent dynamo in the kinematic regime for
different values of the magnetic Reynolds number, ${\rm Rm}$, initial
magnetic-to-kinetic energy ratio, $(E_{\rm{mag}}/E_{\rm{kin}})_{\rm{i}}$, and
initial Larmor ratio, $(r_{\rm Larmor}/L_{\rm box})_{\rm i}$, i.e., the ratio
of the Larmor radius to the size of the turbulent system. We find that in the
`un-magnetised' regime, $(r_{\rm Larmor}/L_{\rm box})_{\rm i} > 1$, the
critical magnetic Reynolds number for the dynamo action ${\rm Rm}_{\rm crit}
\approx 107 \pm 3$. In the `magnetised' regime, $(r_{\rm Larmor}/L_{\rm
box})_{\rm i} \lesssim 1$, we find a marginally higher ${\rm Rm}_{\rm crit} =
124 \pm 8$. We find that the growth rate of the magnetic energy does not depend
on the strength of the seed magnetic field when the initial magnetisation is
fixed. We also study the distribution and evolution of the pressure anisotropy
in the collisionless plasma and compare our results with the MHD turbulent
dynamo.
