ANALYSIS OF THE ELECTROMAGNETIC EFFECTS OF A NUCLEAR EXPLOSION IN THE LOWER ATMOSPHERE
Abstract
From measured waveforms it has been determined that the electromagnetic pulse from a nuclear detonation is associated with the gradual establishment of a large dipole moment, which remains suspended in the atmosphere at the conclusion of the EMP waveform. From the gradual growth and the large magnitude, it is inferred that the source-current region is large, and that retardation across this source-current region is an important aspect of the EMP phenomenon. Retardation is also important in individual processes, since the primary Compton electrons are relativistic, and the forward directivity of their radiated electromagnetic fields can be attributed to retardation and can be encompassed in a distributed-current picture which allows correctly for retardation. When retardation is properly incorporated, it is found that for early times there is a momentary radial electric field projected above the detonation center, with the polarity to drive secondary electrons upward, thereby contributing substantially to the EMP dipole moment. The AFWL non- causal solution gives the wrong polarity for this early-time radial field, but the non-causal parts of the AFWL program can be replaced by a causal iteration procedure, without affecting the parts of the program which deal with electron attachment and air chemistry, and with the gamma rays and the primary source current.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1967
- Accession Number
- AD0826837
Entities
People
- H. T. Li
- Luc Huang
- Roger E. Clapp