  The transition between linear and nonlinear regimes of the mode-coupling
instability (MCI) operating in a monolayer plasma crystal is studied. The mode
coupling is triggered at the centre of the crystal and a melting front is
formed, which travels through the crystal. At the nonlinear stage, the mode
coupling results in synchronisation of the particle motion and the kinetic
temperature of the particles grows exponentially. After melting of the
crystalline structure, the mean kinetic energy of the particles continued to
grow further, preventing recrystallisation of the melted phase. The effect
could not be reproduced in simulations employing a simple point-like wake
model. This shows that at the nonlinear stage of the MCI a heating mechanism is
working which was not considered so far.
