Clad Magic Ring Wigglers.
Abstract
This patent application relates in general to permanent magnet structures for use in electronic devices and, more particularly, to periodic permanent magnetic structures capable of producing magnetic fields greater than the remanence of the magnetic material comprising them. Many devices that employ magnetic fields have heretofore been encumbered by massive solenoids with their equally bulky power supplies. Thus, there has been increasing interest in the application of permanent magnet structures for such uses as electron-beam focusing and biasing fields. The current demand for compact, strong, static magnetic field sources that require no electric power supplies has created needs for permanent magnet structures of unusual form. A number of configurations have been designed and developed for electron beam guidance in millimeter-wave microwave tubes of various types; for dc biasing fields in millimeter wave filters, circulators, isolators, striplines; for field sources in NMR (nuclear magnetic resonance) imagers; and so on. Especially promising for such purposes is the configuration based upon the hollow cylindrical flux source (HCFS) principle described by K. Halbach . A HCFS, sometimes called a 'magic ring,' is a cylindrical permanent magnet shell which produces an internal magnetic field that is more or less constant in magnitude. The field is perpendicular to the axis of the cylinder, and furthermore the field strength can be greater than the remanence of the magnetic material from which the ring is made.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 23, 1988
- Accession Number
- ADD013790
Entities
People
- Herbert A. Leupold
Organizations
- United States Army