Transport of nonlinear oscillations along rays that graze a convex obstacle to any order

Abstract

We provide a geometric optics description in spaces of low regularity, $L^2$ and $H^1$, of the transport of oscillations in solutions to linear and some semilinear second-order hyperbolic boundary problems along rays that graze the boundary of a convex obstacle to arbitrarily high finite or infinite order. The fundamental motivating example is the case where the spacetime manifold is $M=({\mathbb{R}}^n\setminus \mathcal{O})\times {\mathbb{R}}_t$, where $\mathcal{O}\subset {\mathbb{R}}^n$ is an open convex obstacle with $C^{\infty }$ boundary, and the governing hyperbolic operator is the wave operator $\square :=\Delta -{\partial }_t^2$.

71 pages,7 figures. Comments are welcome!