On the validity of the Weak Turbulence Approximation

The weak Langmuir turbulence approach to explain the artificial plasma line in ionospheric radio modification experiments, is examined. The mathematical model is a version of the one dimensional Zakharov equations, including damping and a nonlinear a.c. driving. Numerical full wave solutions to this...

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Bibliographic Details
Main Authors: Hanssen, A., Mjoelhus, E.
Other Authors: TROMSOE UNIV (NORWAY)
Format: Text
Language:English
Published: 1990
Subjects:
Atmospheric Physics
*IONOSPHERIC MODIFICATION
APPROACH
BURNOUT
COLLAPSE
CYCLES
DAMPING
ELECTRONS
EQUATIONS
FREQUENCY
IONS
KINETICS
MATHEMATICAL MODELS
ONE DIMENSIONAL
REFLECTION
REGIONS
SATURATION
THEORY
TURBULENCE
NORWAY
Component Reports
NATO Furnished
Langmuir turbulence
Zakharov equations
Cascade theory
Bergen
Langmuir
Norway
Tromso
Zakharov
Online Access:http://www.dtic.mil/docs/citations/ADP006498
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADP006498
Description
Summary:The weak Langmuir turbulence approach to explain the artificial plasma line in ionospheric radio modification experiments, is examined. The mathematical model is a version of the one dimensional Zakharov equations, including damping and a nonlinear a.c. driving. Numerical full wave solutions to this set of equations are compared with the saturation spectrum determined by a wave kinetic equation derived from the same set of equations. We found that a distance below the 0-mode reflection level, w - wp > (-IM)wp (w applied frequency; wp plasma frequency; m, M electron and ion masses), the full wave solution is in good qualitative agreement with the cascade theory. The number of cascades seen in the full wave solution is generally smaller than that of the saturation spectrum of the wave kinetic equation. On the other hand, in the reflection region w - wp < (m/M)wp, a qualitatively different process takes place, describable as many localized cycles of nucleation, (one dimensional driven) collapse, and burnout, similar to the results of Doolen et al.8. These findings are discussed with respect to the experiments performed in Arecibo and Tromso. This article is from 'Conference Proceedings on Ionospheric Modifications and its Potential to Enchance or Degrade the Performance of Military Systems held in Bergen, Norway on 28-31 MAY 1990 (La Modification de l'Ionosphere et son Potentiel d'Amelioration ou de Degradation des Performances des Systemes Militaires), AD-A239 823, p9-1 thru p9-12.

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