Laser-Induced Sources for Magnetic Fields.
Abstract
Large magnetic fields are produced near the target when a powerful laser pulse is focused onto a solid target. A discussion is given of how the laser radiation produces conditions in the laser-produced plasma which allow the conversion of thermal energy to magnetic field energy. This concept of a thermal source generating the magnetic field is illustrated by deriving the source function for a spherical plasma. It is shown that the necessary nonadiabatic conditions exist in the presence of laser radiation. At a sufficiently high intensity (approximately 10 to the 14th power W/square cm), the linear polarization of the radiation produces a corresponding anisotropy in the electron velocity distribution. Magnetic sources then exist for any spatial variation of pressure and density. Sources due to the direct action of radiation pressure are also discussed. This implies that part of the laser radiation is absorbed by direct conversion (no heating) from laser field energy to magnetic field energy. An estimate is made of the magnetic field produced in the region where laser radiation is being absorbed. Such fields can be quite large--in the megagauss range. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 16, 1972
- Accession Number
- AD0746098
Entities
People
- John A. Stamper
Organizations
- United States Naval Research Laboratory