Mode Conversion in an Oxygen-Hydrogen Plasma.
Abstract
The complications of mode conversion which occur near a minority resonance are studied in the context of electromagnetic ion cyclotron heating of a minority oxygen population in the magnetosphere. This problem is investigated using several different approaches. A perturbation approach demonstrates that the coupling results from non parallel propagation. The phase integral approach involves analytic continuation of (WKB) solutions and involves a discontinuity in the Poynting flux corresponding to energy absorption. The saddle point approach emphasizes the degree to which the coupling can be analyzed in terms of two mode coupling processes. When the two low frequency propagating modes coalesce near the oxygen resonance at two different coupling points, a numerical scheme which retains the two coupling points in a realistic manner is employed, and numerical coefficients are obtained. The calculated coefficients that are presented demonstrate that substantial coupling occurs between the two propagating modes and a definite absorption occurs. Such absorption is sufficient to explain the outflow and heating of ionospheric oxygen ions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 22, 1995
- Accession Number
- ADA299120
Entities
People
- G. B. Crew
- Jay R. Johnson
- Tom Chang
Organizations
- Massachusetts Institute of Technology