  In this work we consider the defocusing nonlinear wave equation in
one-dimensional space. We show that almost all energy is located near the light
cone $|x|=|t|$ as time tends to infinity. We also prove that any light cone
will eventually contain some energy. As an application we obtain a result about
the asymptotic behaviour of solutions to focusing one-dimensional wave equation
with compact-supported initial data.

Analysis of PDEs