Caviton dynamics in strong Langmuir turbulence
Recent studies based on long time computer simulations of Langmuir turbulence as described by Zakharov's model will be reviewed. These show that for strong to moderate ion sound samping the turbulent energy is dominantly 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. These observations and theoretical considerations also strongly imply that cavitons in the heated ionosphere, under certain conditions, 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. 40 refs., 19 figs.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 6067377
- Report Number(s):
- LA-UR-89-1848; CONF-8905156-1; ON: DE89012635
- Resource Relation:
- Journal Volume: T30; Conference: International Centre for Theoretical Physics conference, Trieste, Italy, 22 May 1989; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
Similar Records
Excitation of strong Langmuir turbulence in plasmas near critical density: Application to HF heating of the ionosphere
Concepts in strong Langmuir turbulence theory
Related Subjects
GENERAL PHYSICS
IONOSPHERE
TURBULENCE
PLASMA WAVES
CAVITATION
COMPUTERIZED SIMULATION
DYNAMICS
ELECTRIC FIELDS
ENERGY SPECTRA
LANDAU DAMPING
SOUND WAVES
SPACE-TIME
DAMPING
EARTH ATMOSPHERE
MECHANICS
PLANETARY IONOSPHERES
SIMULATION
SPECTRA
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena