Nonlinear behavior of weakly unstable linear modes in plasmas with aligned equilibrium mass flow

Journal Article · Sat Sep 01 00:00:00 EDT 1990 · Physics of Fluids B; (USA)

DOI:https://doi.org/10.1063/1.859427· OSTI ID:6412246

Peredo, M; Tataronis, J A ^[1]

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1. Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, WI (USA)

The nonlinear evolution of weakly unstable linear magnetohydrodynamic waves in plasma configurations characterized by equilibrium mass flow aligned parallel to the magnetic field is investigated. The analysis is based on field representations expressed as expansions in Fourier harmonics and computation of modifications to the linear theory (first harmonic) arising from the nonlinear coupling between the zeroth and second harmonics. It is found that Landau's equation governs the nonlinear evolution of the system. A correction to the linearized theory appears at third order in the mode amplitude and is proportional to the linear growth rate. Furthermore, the conditions under which the nonlinearities provide a saturation mechanism to limit the growth of the linear instabilities is explored. Finally, this saturation phenomenon for a specific configuration consisting of a Z pinch with a small axial magnetic field is illustrated.

• OSTI ID: 6412246
• Journal Information: Physics of Fluids B; (USA), Vol. 2:9; ISSN 0899-8221
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
PLASMA
NONLINEAR PROBLEMS
PLASMA DRIFT
EQUILIBRIUM
CORRECTIONS
COUPLING
FOURIER ANALYSIS
HARMONICS
INSTABILITY GROWTH RATES
LINEAR Z PINCH DEVICES
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MASS TRANSFER
MODIFICATIONS
OSCILLATION MODES
SATURATION
FLUID MECHANICS
HYDRODYNAMICS
LINEAR PINCH DEVICES
MECHANICS
OPEN PLASMA DEVICES
OSCILLATIONS
PINCH DEVICES
THERMONUCLEAR DEVICES
700107* - Fusion Energy- Plasma Research- Instabilities
700103 - Fusion Energy- Plasma Research- Kinetics