A Coherent Nonlinear Theory of Auroral Kilometric Radiation. II. Dynamic Interactions.
Abstract
We present an extension of the analysis of our previously proposed model for auroral kilometric radiation, in which the full three-wave dynamics is considered. The temporal variation of the electrostatic ion cyclotron density fluctuations and the effect of a finite three-wave coupling coefficient, both effects ignored in our steady state theory, are included here. This yields a set of coupled three-wave kinetic equations, which are solved numerically for the evolution of the auroral kilometric radiation. The numerical results tend to confirm all of the predictions of our steady state theory. The growth rate is found to be determined by the resonant growth rate found in our steady state theory, and stages of the growth are found in which the radiation grows at twice the resonant growth rate, and sometimes four, eight, etc. times that value. The growth saturates, and this saturation level is found to scale where the rate of transfer of energy from the beam to the beat wave, or quasimode. Saturation levels are found which are adequate to produce the observed radiation levels. It is found that for a sufficiently large growth region, the saturation level is relatively independent of the initial level of density fluctuations. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 27, 1981
- Accession Number
- ADA096895
Entities
People
- Crockett L. Grabbe
- Peter J. Palmadesso
Organizations
- United States Naval Research Laboratory