We describe analytically and numerically the quasi-classical collapse of strong lower-hybrid waves. Such collapse leads to two disparate scales corresponding to macro and micro structures due to the nonlinear interaction. The wavelength of waves trapped within the cavity are much smaller than the cavity dimension and decrease during the collapse process much faster. We obtain self-similar solutions describing this phenomenon, which conserves the number of trapped wave quanta, corresponding to strong collapse and compare the results with a particle in cell simulation.
