Graduate School in Nonlinear Science
Sponsored by the Danish Research Academy
Role of the Critical Collapse Singularity in forming and sustaining Nonlinear
Waveguides in Air
by J.V. Moloney
Arizona Center for Mathematical Sciences
University of Arizona, Tucson
Tuesday, June 30, 1998 14:00 h
at MIDIT, Building 305 room 027
MIDIT-seminar No. 410
Abstract: High power femtosecond duration laser pulses can
undergo critical collapse while propagating in air.
Two distinct physical mechanisns can arrest the formation of the critical
collapse singularity. Weak normal group velocity dispersion may cause the
laser pulse to split in two with the posibility of further collapse and splittings.
Alternatively a weak plasma filament can form and limit the explosive intensity
This weak dissipation causes the collapsing filament to decay.
However the background reservoir of energy, not contained in the collapsing
filament, can feed subsequent collapses leading to a novel dynamic waveguiding