Plasma Modification Associated with Parametric Instabilities Driven by Intense Electromagnetic Waves
Abstract
The purpose of the experimental effort is to study, in laboratory plasma, effects relating to observations of enhanced absorption of electromagnetic waves in the ionosphere. The experiments were performed in a Q- machine plasma, which has comparable ion and electron temperatures, similar to the ionosphere. The isothermal (T sub e about = (T sub i) parametric ion acoustic decay instability, expected to cause modification of the ionosphere upon irradiation by intense electromagnetic waves (omega sub 0) < or = (omega sub pe), has been studied in detail in laboratory Q-machine plasmas. The instability is conclusively identified by wavelength and frequency measurements, over all parameters determined ranges (k (lambda sub de) < or = 0.2; (omega sub LF)/(omega sub pi) < or = 1). Other parameters determined are instability threshold and maximum acoustic frequency dependence upon density; instability bandwidths and spatial profiles; electron and ion heating--all in agreement with linear, homogeneous theory. Not in agreement with theory are relations between LF, HF and pump intensities. (Modified author abstract)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1974
- Accession Number
- AD0780033
Entities
People
- Hans W. Hendel
- James T. Flick
Organizations
- Princeton University