Propagation of nonlinear acoustic waves in gallium

We study nonlinear phenomena which occur during strong sound signal propagation in superpure Ga and are due to the perturbation of the electron subsystem in the metal. Although the observations are in qualitative agreement with theoretical concepts in a number of aspects, there are effects which still lack adequate theoretical interpretation, in particular, an oscillatory dependence of the harmonic amplitudes on magnetic field which is linear with respect toH^1/2, and appreciable nonlinear distortions of the sound pulse envelope accompanied by the acoustic noise generation.