[en] Using a kinetic description, the relativistically strong Langmuir turbulence is investigated, which has considered the nonlinear wave-wave, wave-particle interactions and the relativistic effects of electrons. The relativistic Zakharov equations have been obtained. On the basis of these equations, dynamics of collapse has been studied. It is shown that the field strength of relativistic Langmuir plasmons will increase and the ponderomotive expulsion of particles gives rise to the formation of density caviton during the collapsing, which is useful for understanding the natural structural element of relativistically strong Langmuir turbulence.