Collapse of ultra-short pulse of electromagnetic field within non-linear\n electrodynamics

We analyze the development of pulse instability within non-linear\nelectrodynamics based on the Maxwell's equations, without the approximation of\nslowly varying amplitudes and phases. The action is determined on the basis of\nthe logarithmic and exponential Lagrangians, built on the invariants of the\nelectromagnetic field. It is shown that the onset of the collapse of an\nultra-short pulse of the electromagnetic field in the framework of nonlinear\nelectrodynamics.\n