Decay instability of gravity-capillary waves on liquid hydrogen surfaces

Experiments on the decay instability of gravity-capillary waves excited by alternating electric fields with frequencies of 14-30 Hz on a charged liquid hydrogen surface in a rectangular cell are reported. An exponential increase in the amplitudes of the subharmonics caused by decay of the wave at the pump frequency is found. For the first time, the experimentally observed growth rate of the decay instability and damping coefficient for the surface waves in the rectangular cell yield an estimate of the coefficient for three-wave interactions of gravity-capillary waves in liquid hydrogen. Published by AIP Publishing.