Dynamical decoupling and recoupling of the Wigner solid to a liquid helium substrate

We investigate the dynamical interaction between an electron crystal trapped above the surface of liquid helium and surface waves (`ripplons') excited by its motion. At rest, the electron system is `dressed' by static ripplons to form `ripplopolaron' states. As the electrons move, resonant ripplon scattering results in a growth of the ripplopolaron effective mass, on timescales comparable with the inverse of the ripplon frequency ($\ensuremath{\sim}100$ ns). Under sufficient driving force, the electron system decouples from the surface waves and moves at high velocity, before decelerating sharply when the electron solid and surface excitations recouple to form a `new' ripplopolaron system. The mass of the newly formed ripplopolarons is similar to that in the initial static case.