Effect of wave localization on plasma instabilities. Ph. D. Thesis

Technical Report · Thu Oct 01 04:00:00 EDT 1987

OSTI ID:5151286

Levedahl, W K

The Anderson model of wave localization in random media is involved to study the effect of solar wind density turbulence on plasma processes associated with the solar type III radio burst. ISEE-3 satellite data indicate that a possible model for the type III process is the parametric decay of Langmuir waves excited by solar flare electron streams into daughter electromagnetic and ion acoustic waves. The threshold for this instability, however, is much higher than observed Langmuir wave levels because of rapid wave convection of the transverse electromagnetic daughter wave in the case where the solar wind is assumed homogeneous. Langmuir and transverse waves near critical density satisfy the Ioffe-Reigel criteria for wave localization in the solar wind with observed density fluctuations -1 percent. Numerical simulations of wave propagation in random media confirm the localization length predictions of Escande and Souillard for stationary density fluctations. For mobile density fluctuations localized wave packets spread at the propagation velocity of the density fluctuations rather than the group velocity of the waves. Computer simulations using a linearized hybrid code show that an electron beam will excite localized Langmuir waves in a plasma with density turbulence. An action principle approach is used to develop a theory of non-linear wave processes when waves are localized. A theory of resonant particles diffusion by localized waves is developed to explain the saturation of the beam-plasma instability. It is argued that localization of electromagnetic waves will allow the instability threshold to be exceeded for the parametric decay discussed above.

• Research Organization: California Univ., Berkeley, CA (USA)
• OSTI ID: 5151286
• Report Number(s): N-89-30075; NASA-CR--184908; NAS--1.26:184908
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DAMPING
DATA
ELECTROMAGNETIC RADIATION
INFORMATION
INSTABILITY
ION ACOUSTIC WAVES
ION WAVES
LANDAU DAMPING
MATHEMATICAL MODELS
NUMERICAL DATA
PLASMA INSTABILITY
PLASMA WAVES
RADIATIONS
RADIOWAVE RADIATION
SOLAR ACTIVITY
SOLAR FLARES
SOLAR WIND
THEORETICAL DATA
WAVE PROPAGATION