2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/119552The transition from spatial to spatiotemporal dynamics in Kerr-driven beam collapse is modelled as the instability of the Townes profile. Coupled axial and conical radiation, temporal splitting and X waves appear as the effect of Y-shaped unstable modes, whose growth is experimentally detected.4 pages, 3 figuresOpticstext