ELECTROMAGNETIC INDUCTION ON AN EXPANDING CONDUCTING SPHERE,
Abstract
This report concerns a theoretical investigation of the electromagnetic fields associated with the radial expansion of a spherical conductor immersed in an originally uniform, static, magnetic field. Radial expansion, as used here, implies an increase in size without change of geometrical shape. The conducting sphere of initial radius a sub o in a static magnetic field which, in the absence of the sphere, is uniform. At a certain time (t=0) the sphere begins to expand. The radius of the sphere is a prescribed arbitrary function of time, a(t). Since the sphere is electrically conducting, its interaction with the magnetic field as it expands results in the induction of currents that, to a greater or lesser extent, shield the magnetic field from the interior of the sphere. The determination of the fields generated by these currents is the objective of this research. In general, it is necessary to prescribe not only the time dependence of the radius but also the velocity as a function of space and time for all points inside the sphere. The forces that are necessary to cause the expansion are assumed to exist, but are not prescribed. Once the fields and currents are found, these forces can be determined. The cases of perfect and imperfect conductivity will be investigated. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 30, 1964
- Accession Number
- AD0602435
Entities
People
- Luiz C. Bahiana
Organizations
- Massachusetts Institute of Technology