Dynamics of cavitons in strong Langmuir turbulence

Conference · Mon Jan 01 04:00:00 EST 1990

DOI:https://doi.org/10.1088/0031-8949/1990/T30/020· OSTI ID:7103693

DuBois, D F; Rose, H A; Russell, D

Recent studies of Langmuir turbulence as described by Zakharov's model will be reviewed. For parameters of interest in laser-plasma experiments and for ionospheric hf heating experiments a significant fraction of the turbulent energy is in nonlinear caviton'' excitations which are localized in space and time. A local caviton model will be presented which accounts for the nucleation-collapse-burnout cycles of individual cavitons as well as their space-time correlations. This model is in detailed agreement with many features of the electron density fluctuation spectra in the ionosphere modified by powerful hf waves as measured by incoherent scatter radar. Recently such observations have verified a prediction of the theory that free'' Langmuir waves are emitted in the caviton collapse process. Observations and theoretical considerations also imply that when the pump frequency is slightly lower than the ambient electron plasma frequency cavitons may evolve to states in which they are ordered in space and time. The sensitivity of the high frequency Langmuir field dynamics to the low frequency ion density fluctuations and the related caviton nucleation process will be discussed. 42 refs., 12 figs.

• Research Organization: Los Alamos National Lab., NM (USA)
• Sponsoring Organization: DOE/DP
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 7103693
• Report Number(s): LA-UR-90-1000; CONF-900264--4; ON: DE90008918
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CAVITATION
COMPARATIVE EVALUATIONS
DYNAMICS
EARTH ATMOSPHERE
ELECTROMAGNETIC RADIATION
ELECTRON DENSITY
ENERGY-LEVEL TRANSITIONS
EXCITATION
FLUCTUATIONS
FREQUENCY ANALYSIS
ION DENSITY
IONOSPHERE
LANGMUIR FREQUENCY
LASERS
MATHEMATICAL MODELS
MECHANICS
PERFORMANCE TESTING
PLANETARY IONOSPHERES
PLASMA WAVES
POWER DENSITY
RADIATIONS
RADIOWAVE RADIATION
SCATTERING
SENSITIVITY
SPACE-TIME
TESTING
TURBULENCE
VARIATIONS
VERIFICATION