NON-LINEAR EFFECTS IN ELECTRON PLASMAS

Journal Article · Sun Jan 01 04:00:00 EST 1961 · J. Nuclear Energy, Pt. C. Plasma Phys.-Accelerators-Thermonuclear Research

DOI:https://doi.org/10.1088/0368-3281/2/1/325· OSTI ID:4020115

Sturrock, P A

The effect of non-linear terms in the dynamical equations governing wave propagation in plasmas may be analyzed by a perturbation procedure that is acceptable for amplitudes that are not too large. The Hamiltonian describing the complete system is separated into 2 parts: the quadratic part that yields the linearized equations, and the non-linesr psrt. The quadratic part may be eliminated by a normal-mode analysis, the "normal modes" comprising traveling waves. The non-linear part then results in interaction between these waves. Two theorems concerning wave interaction are proved. The first relates energytransfer between a group of interacting waves to the frequency of these waves. This "action-transfer relations" lead to relations for steady-state or quasi-steady-state configurations. The second theorem relates the frequencydisplacements of a group of interacting waves to the energies of these waves. The properties of electron plasmss undergoing longitudinal oscillations are examined in the light of the preceding theorems. Interaction terms may be classed as "coherent" and "incoherent": the former do not result in energy transfer but only frequency displacement which may be characterized by a dispersion relation. The second group leads to transfer of energy between waves and hence to spectral decay. The interaction between longitudinal (electrostatic) and transverse (electromagnetic) waves in plasmas is considered and it is shown that in a uniform plasma in the absence of magnetic fields, the dominant interaction couples 2 longitudinal waves with 1 transverse wave. The dominant non-linear mechanism for radiation from excited plasmas should lead to emission at twice the plasma frequency. (auth)

• Research Organization: Stanford Univ., Calif.
• NSA Number: NSA-15-017678
• OSTI ID: 4020115
• Journal Information: J. Nuclear Energy, Pt. C. Plasma Phys.-Accelerators-Thermonuclear Research, Journal Name: J. Nuclear Energy, Pt. C. Plasma Phys.-Accelerators-Thermonuclear Research Vol. Vol: 2
• Country of Publication: Country unknown/Code not available
• Language: English

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