Title: The Universal Route to Rogue Waves via Instanton Theory

Abstract: In stochastic systems, extreme events are known to be described by
“instantons”, saddle point configurations of the action of the
associated stochastic field theory. In this talk, I will present
experimental evidence of a hydrodynamic instanton in a real world fluid
system: A 270m wave channel experiment in Norway. The experiment
attempts to model conditions on the ocean in order to observe so-called
rogue waves, realisations of extreme ocean surface elevation out of
relatively calm surroundings. These rogue waves are also observed in the
ocean, where they are rare and hard to predict but pose significant
danger to naval vessels. We show that the instanton approach, which is
rigorously grounded in large deviation theory, offers a unified
description of rogue waves in the water tank, covering the entire range
of parameters for deep water waves in the ocean. In particular, this
approach allows for a unified description of both the predominantly
linear and the highly nonlinear regimes, and is able to predict the
experimental data in the tank regardless of the strength of the
nonlinearity.