Stokes waves with vorticity

The existence of periodic waves propagating downstream on the surface of a two-dimensional infinitely deep water under gravity is established for a general class of vorticities. When reformulated as an elliptic boundary value problem in a fixed semi-infinite strip with a parameter, the operator describing the problem is nonlinear and non-Fredholm. A global connected set of nontrivial solutions is obtained via singular theory of bifurcation. Each solution on the continuum has a symmetric and monotone wave profile. The proof uses a generalized degree theory, global bifurcation theory and Wyburn's lemma in topology, combined with the Schauder theory for elliptic problems and the maximum principle

Shielding at a distance due to anomalous resonance in superlens with eccentric core

A cylindrical plasmonic structure with a concentric core exhibits an anomalous localized resonance which results in cloaking effects. Here we show that, if the structure has an eccentric core, a new kind of shielding effect can happen. In contrast to the conventional shielding device, our proposed structure can block the effect of external electrical sources even on a region which is not enclosed by any conducting materials. In fact, the shielded region is located at a distance from the device. We analytically investigate this phenomenon by using the m\"{o}bius transformation via which an eccentric annulus is transformed into a concentric one. We also present several numerical examples.Comment: 11 pages, 6 figure