{ "id": "1902.00513", "version": "v1", "published": "2019-02-01T20:29:04.000Z", "updated": "2019-02-01T20:29:04.000Z", "title": "On the dynamics of a charged particle in magnetic fields with cylindrical symmetry", "authors": [ "Paolo Caldiroli", "Gabriele Cora" ], "comment": "19 pages, 1 figure", "categories": [ "math.DS", "math.FA" ], "abstract": "We study the motion of a charged particle under the action of a magnetic field with cylindrical symmetry. In particular we consider magnetic fields with constant direction and with magnitude depending on the distance $r$ from the symmetry axis of the form $1 + Ar^{-\\gamma}$ as $r\\to\\infty$, with $A\\ne 0$ and $\\gamma > 1$. With perturbative-variational techniques, we can prove the existence of infinitely many trajectories whose projection on a plane orthogonal to the direction of the field describe bounded curves given by the superposition of two motions: a rotation with constant angular speed at a unit distance about a point which moves along a circumference of large radius $\\rho$ with a slow angular speed $\\varepsilon$. The values $\\rho$ and $\\varepsilon$ are suitably related to each other. This problem has some interest also in the context of planar curves with prescribed curvature.", "revisions": [ { "version": "v1", "updated": "2019-02-01T20:29:04.000Z" } ], "analyses": { "keywords": [ "magnetic field", "cylindrical symmetry", "charged particle", "constant direction", "planar curves" ], "note": { "typesetting": "TeX", "pages": 19, "language": "en", "license": "arXiv", "status": "editable" } } }