Parametric instabilities with finite wavelength pump

Journal Article · Wed Dec 01 04:00:00 EST 1976 · Phys. Fluids; (United States)

DOI:https://doi.org/10.1063/1.861428· OSTI ID:7132591

Fried, B D; Ikemura, T; Nishikawa, K; Schmidt, G

The general problem of parametric instabilities driven by a finite wavelength pump is investigated. For the particular case of a Langmuir wave pump, it is shown that resonant decay instabilities (forward or backward scattering in the one-dimensional case), with thresholds which vanish in the colisionless limit, can occur only for pump wavenumber k/sub 0/ greater than the critical value ((m/M)/sup 1///sup 2//..gamma..)k/sub D/, where m and M are the electron and the ion mass, respectively, and ..gamma.. is the specific heat ratio. For smaller wavenumbers, there is always a nonzero threshold, the instability being of modulation character at long wavelengths and almost pure growing for short wavelengths. Frequency locking for small k/sub 0/ and wavenumber locking for large k/sub 0/ are demonstrated. The results are generalized to the case where the coupled waves satisfy arbitrary dispersion relations and simple physical interpretations of the instabilities are given. (AIP)

• Research Organization: Department of Physics, University of California, Los Angeles, California 90024
• OSTI ID: 7132591
• Journal Information: Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 19:12; ISSN PFLDA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
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700108 -- Fusion Energy-- Plasma Research-- Wave Phenomena
DECAY INSTABILITY
INSTABILITY
ION ACOUSTIC WAVES
ION WAVES
PARAMETRIC INSTABILITIES
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PLASMA MICROINSTABILITIES
PLASMA WAVES
TWO-STREAM INSTABILITY