Dynamics of cavitons in strong Langmuir turbulence
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 Laboratory (LANL), Los Alamos, NM (United States)
- 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
- Resource Relation:
- Journal Volume: T30; Conference: Topical conference on research trends in nonlinear and relativistic effects in plasmas, San Diego, CA (USA), 5-8 Feb 1990
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
CAVITATION
DYNAMICS
IONOSPHERE
TURBULENCE
COMPARATIVE EVALUATIONS
ELECTRON DENSITY
EXCITATION
FLUCTUATIONS
FREQUENCY ANALYSIS
ION DENSITY
LANGMUIR FREQUENCY
LASERS
MATHEMATICAL MODELS
PERFORMANCE TESTING
PLASMA WAVES
POWER DENSITY
RADIOWAVE RADIATION
SCATTERING
SENSITIVITY
SPACE-TIME
VERIFICATION
EARTH ATMOSPHERE
ELECTROMAGNETIC RADIATION
ENERGY-LEVEL TRANSITIONS
MECHANICS
PLANETARY IONOSPHERES
RADIATIONS
TESTING
VARIATIONS
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena