The Angular Distribution of Auroral Kilometric Radiation.
Abstract
Measurements of the angular distribution of auroral kilometric radiation (AKR) are presented using observations from the Hawkeye 1, IMP 6, and IMP 8 satellites. The wave experiments on Hawkeye 1 and IMP 6 provide electric field measurements of AKR in narrow frequency bands centered at 178, 100, and 56.2 kHz and IMP 8 provides measurements at 500 kHz. From a frequency of occurrence survey, at satellite radial distances greater than 7 Re (earth radii) it is shown that AKR is preferentially and instantaneously being beamed into solid angles of approximately 3.5 steradians at 178 kHz, 1.8 steradians at 100 kHz, and 1.1 steradians at 56.2 kHz, directed upward from the night time auroral zones. Simultaneous multiple satellite observations of AKR in the northern hemisphere show that the radiation occurs simultaneously throughout these solid angles and that the topside plasmapause acts as an abrupt propagation cutoff on the nigh side of the earth. On the day side of the earth this abrupt cutoff at the plasmapause is not observed. The results of a computer ray tracing model qualitatively describing the propagation characteristics of AKR are also discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1976
- Accession Number
- ADA033218
Entities
People
- Donald A. Gurnett
- J. L. Green
- S. D. Shawhan
Organizations
- University of Iowa