Measuring and Interpreting ELF Signals during a PCA Aspects of an Experimental Design.
Abstract
Investigates the design of a transpolar extremely-low-frequency (ELF) experiment that would validate Defense Nuclear Agency propagation codes for ELF system performance in nuclear environments. To be conducted during the next solar maximum, when polar cap absorption events (PCAs) might approximate a nuclear environment, the ideal experiment would simultaneously measure both propagation and ionospheric structure. Propagation measurements would be taken at receivers located such that the direct propagation path did not approach the polar cap boundary; the ELF values would then be compared with computer code outputs. A moderate PCA might cause a 3 to 4 dB reduction in a transpolar ELF signal; a strong event, an 8 or 9 dB reduction. At least 2 hours would be required to resolve amplitude changes in the signal; noise processing to excise large pulses would be essential. Measurements of ionospheric changes would be taken with rocket-borne instruments, entered into computer calculations using the DNA codes, then compared with the propagation measurements. Rocket data should be gathered at 50 km or below; data from previous PCAs obtained only at 60 km or above yield unacceptable uncertainties in calculated field strengths. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1979
- Accession Number
- ADA090121
Entities
People
- E. C. Field Jr.
- R. N. Dewitt