Interaction of "Solitons" in a Collisionless Plasma and the Recurrence of Initial States

This article appears in the following collection:Letters from the Past - A PRL Retrospective2008 marked PRL's 50th anniversary. As part of the celebrations a collection of milestone Letters was started. The collection contains Letters that have made long-lived contributions to physics, either by announcing significant discoveries, or by initiating new areas of research.