ИСТИНА

We demonstrate that a strongly ionized region of a filament can be succeeded by a much longer light channel, where a stable self-guiding spatial mode is sustained by the high-order Kerr effect. In the limiting regime of negligibly low ionization, as our analysis shows, this post-filamentation beam dynamics converges to a large-scale beam self-trapping cenario predicted many decades ago in the classical texts on nonlinear optics.