  A two-dimensional particle-in-cell simulation is performed to investigate
weakly magnetized perpendicular shocks with a magnetization parameter of 6 x
10^-5, which is equivalent to a high Alfv\'en Mach number M_A of ~130. It is
shown that current filaments form in the foot region of the shock due to the
ion-beam--Weibel instability (or the ion filamentation instability) and that
they generate a strong magnetic field there. In the downstream region, these
current filaments also generate a tangled magnetic field that is typically 15
times stronger than the upstream magnetic field. The thermal energies of
electrons and ions in the downstream region are not in equipartition and their
temperature ratio is T_e / T_i ~ 0.3 - 0.4. Efficient electron acceleration was
not observed in our simulation, although a fraction of the ions are accelerated
slightly on reflection at the shock. The simulation results agree very well
with the Rankine-Hugoniot relations. It is also shown that electrons and ions
are heated in the foot region by the Buneman instability (for electrons) and
the ion-acoustic instability (for both electrons and ions). However, the growth
rate of the Buneman instability is significantly reduced due to the relatively
high temperature of the reflected ions. For the same reason, ion-ion streaming
instability does not grow in the foot region.
