Linear and non-linear excitation of slow waves in the ion cyclotron frequency range

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5464181

Skiff, F N

Linear and nonlinear excitation of slow waves in the ion cyclotron frequency range were studied in a finite-ion-temperature magnetized plasma. Loop antennas designed to induce electric fields either parallel or perpendicular to the static magnetic field were used to investigate coupling to the ion Bernstein wave (IBW). The experiments are modeled and the plasma is described using a self-adjoint equation that includes ion kinetic effects. Both in theory and experiment, the antenna loading is found to be insensitive to antenna polarization. Faraday shielded fast wave polarized antennas (previously thought not to excite slow waves) are shown to couple to the IBW by means of the plasma density gradient. The dependence of Bernstein wave radiation resistance on plasma density, parallel wavenumber, and wave frequency are investigated. Nonlinear (parametric) excitation of ion Bernstein waves is observed and the wave-wave coupling is compared to uniform pump theory. Variation of the decay growth rate with pump wave frequency and plasma density (collisionality) are observed. Harmonic generation associated with the use of electrostatic plate antennas is observed and found to agree with sheath rectification. Subsequent parametric coupling of the second harmonic (lower hybrid) wave with a nonresonant quasimode and with the slow ion cyclotron wave are observed. Decay wave amplitude scaling indicates nonlinear saturation of the process.

• Research Organization: Princeton Univ., NJ (USA)
• OSTI ID: 5464181
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700108* -- Fusion Energy-- Plasma Research-- Wave Phenomena
ANTENNAS
BERNSTEIN MODE
COUPLING
ELECTRICAL EQUIPMENT
ENERGY-LEVEL TRANSITIONS
EQUIPMENT
EXCITATION
HARMONICS
OSCILLATION MODES
OSCILLATIONS
PLASMA DENSITY
PLASMA WAVES