Kinetic theory of two-plasmon decay

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5868304

Powers, L V

The two-plasmon decay instability, in which a large amplitude transverse (pump) wave decays into two Langmuir waves, is analyzed within the framework of the Vlasov-Maxwell equations. The effects of Landau damping and temperature-dependent kinetic theory corrections to the coupling strength are examined for spatially and temporally unstable modes. Landau damping is found to significantly reduce the growth of the instability in a homogeneous plasma even at modest temperatures (T approx.> 1 keV). The most unstable modes move to smaller wavenumbers as the temperature increases and have wavenumbers comparable to the pump wavenumber k/sub 0/ above 5 keV. Conditions for the existence of unstable eigenmodes in a weakly inhomogeneous plasma are found in the WKB approximation for obliquely scattered Langmuir waves. The analysis shows that the crucial feature that allows the existence of eigenmodes is the spatial dependence of the coupling. The growth of spatially amplifying modes is found to be less sensitive to Landau damping. Amplification is possible over a wide range of wavenumbers. At high temperatures, maximum growth occurs when one Langmuir wave is nearly sidescattered, and kinetic theory corrections are important in determining growth rates and thresholds.

• Research Organization: Michigan Univ., Ann Arbor (USA)
• OSTI ID: 5868304
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700107 -- Fusion Energy-- Plasma Research-- Instabilities
700108* -- Fusion Energy-- Plasma Research-- Wave Phenomena
DAMPING
DECAY INSTABILITY
EQUATIONS
INHOMOGENEOUS PLASMA
INSTABILITY
KINETIC EQUATIONS
LANDAU DAMPING
PLASMA
PLASMA INSTABILITY
PLASMA WAVES
PLASMONS
QUASI PARTICLES